HOME

TheInfoList



OR:

Twilight is
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
produced by
sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...
scattering Scattering is a term used in physics to describe a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including ...
in the upper
atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
, when the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this illumination occurs. The lower the Sun is beneath the horizon, the dimmer the twilight (other factors such as atmospheric conditions being equal). When the Sun reaches 18° below the horizon, the twilight's brightness is nearly zero, and
evening Evening is the period of a day that starts at the end of the afternoon and overlaps with the beginning of night. The exact times when evening begins and ends depend on location, time of year, and culture, but it is generally regarded as beginn ...
twilight becomes
night Night (also described as night time, unconventionally spelled as "nite") is the period of ambient darkness from sunset to sunrise during each 24-hour day, when the Sun is below the horizon. The exact time when night begins and ends depends o ...
time. When the Sun again reaches 18° below the horizon, nighttime becomes morning twilight. Owing to its distinctive quality, primarily the absence of
shadow A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, o ...
s and the appearance of objects
silhouette A silhouette ( , ) is the image of a person, animal, object or scene represented as a solid shape of a single colour, usually black, with its edges matching the outline of the subject. The interior of a silhouette is featureless, and the silhou ...
d against the lit sky, twilight has long been popular with photographers and painters, who often refer to it as the
blue hour The blue hour (from French ; ) is the period of twilight (in the morning or evening, around the nautical stage) when the Sun is at a significant depth below the horizon. During this time, the remaining sunlight takes on a mostly blue shade. T ...
, after the
French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...
expression ''l'heure bleue''. By analogy with evening twilight, the word ''twilight'' is also sometimes used
metaphor A metaphor is a figure of speech that, for rhetorical effect, directly refers to one thing by mentioning another. It may provide (or obscure) clarity or identify hidden similarities between two different ideas. Metaphors are often compared wit ...
ically, to imply that something is losing strength and approaching its end. For example, very old people may be said to be "in the twilight of their lives". The
collateral adjective A collateral adjective is an adjective that is identified with a particular noun in meaning, but that is not derived from that noun. For example, the word ''bovine'' is considered the adjectival equivalent of the noun ''cow'', but it is derived from ...
for ''twilight'' is ''
crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of daylig ...
'', which may be used to describe the behavior of animals that are most active during this period.


Definitions by geometry

Twilight is defined according to the
solar elevation angle The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction. It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the s ...
''θs'', which is the position of the geometric center of the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
relative to the horizon. There are three established and widely accepted ''subcategories'' of twilight: civil twilight (nearest the horizon), nautical twilight, and astronomical twilight (farthest from the horizon).


Civil twilight

Civil twilight is the period when enough natural light remains that artificial light is not needed. Morning civil twilight begins when the geometric center of the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
is 6° below the
horizon The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether i ...
ftp://ftp.flaterco.com/xtide/Bowditch.pdf#238 The American Practical Navigator, 2002; page 238http://www.ast.cam.ac.uk/public/ask/2445 University of Cambridge – Institute of Astronomy – Ask an Astronomer ''NB: questionable source as its sources refer back to Wikipedia/ref> and ends at
sunrise Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning. The term can also refer to the entire process of the solar disk crossing the horizon and its accompanying atmospheric effects. Terminology Al ...
. Evening civil twilight begins at
sunset Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation. As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring ...
and ends when the geometric center of the sun reaches 6° below the horizon. In the United States' military, the
initialisms An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...
BMCT (begin morning civil twilight, ''i.e.'' civil dawn) and EECT (end evening civil twilight, ''i.e.'' civil dusk) are used to refer to the start of morning civil twilight and the end of evening civil twilight, respectively. Civil dawn is preceded by morning nautical twilight and civil
dusk Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, enou ...
is followed by evening nautical twilight. Under clear weather conditions, civil twilight approximates the limit at which solar illumination suffices for the human eye to clearly distinguish terrestrial objects. Enough illumination renders artificial sources unnecessary for most outdoor activities. At civil dawn and at civil dusk sunlight clearly defines the horizon while the brightest stars and planets can appear. As observed from the Earth (see
apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...
), sky-gazers know
Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
, the brightest planet, as the "morning star" or "evening star" because they can see it during civil twilight. Lawmakers have enshrined the concept of civil twilight. Such statutes typically use a fixed period after sunset or before sunrise (most commonly 20–30 minutes), rather than how many degrees the Sun is below the horizon. Examples include when drivers of automobiles must turn on their headlights (called
lighting-up time In the United Kingdom, lighting-up time is a legally-enforced period from half an hour after sunset to half an hour before sunrise, during which all motor vehicles on unlit public roads (except if parked) must use their headlights. History Li ...
in the UK), when hunting is restricted, or when the crime of
burglary Burglary, also called breaking and entering and sometimes housebreaking, is the act of entering a building or other areas without permission, with the intention of committing a criminal offence. Usually that offence is theft, robbery or murder ...
is to be treated as nighttime burglary, which carries stiffer penalties in some jurisdictions. The period may affect when extra equipment, such as anti-collision lights, is required for aircraft to operate. In the US, civil twilight for aviation is defined in Part 1.1 of the
Federal Aviation Regulations The Federal Aviation Regulations (FARs) are rules prescribed by the Federal Aviation Administration (FAA) governing all aviation activities in the United States. The FARs comprise Title 14 of the Code of Federal Regulations (CFR). A wide variety o ...
(FARs) as the time listed in the American Air Almanac.


Nautical twilight

Morning nautical twilight (nautical dawn) begins when the geometric center of the Sun is 12 degrees below the horizon in the morning and ends when the geometric center of the Sun is 6 degrees below the horizon in the morning.Evening nautical twilight (nautical dusk) begins when the geometric center of the Sun is 6 degrees below the horizon in the evening and ends when the geometric center of the Sun is 12 degrees below the horizon in the evening. Before nautical dawn and after nautical dusk, sailors cannot navigate via the horizon at sea as they cannot clearly see the horizon. At nautical dawn and nautical dusk, the human eye finds it difficult, if not impossible, to discern traces of illumination near the sunset or sunrise point of the horizon (''first light'' after nautical dawn but before civil dawn and ''nightfall'' after civil dusk but before nautical dusk). Sailors can take reliable star sightings of well-known stars, during the stage of nautical twilight when they can distinguish a visible horizon for reference (i.e. after astronomic dawn or before astronomic dusk). Under good atmospheric conditions with the absence of other illumination, during nautical twilight, the human eye may distinguish general outlines of ground objects but cannot participate in detailed outdoor operations. Nautical twilight has military considerations as well. The initialisms BMNT (begin morning nautical twilight, ''i.e.'' nautical dawn) and EENT (end evening nautical twilight, ''i.e.'' nautical dusk) are used and considered when planning military operations. A military unit may treat BMNT and EENT with heightened security, e.g. by "standing to", in which everyone assumes a defensive position.


Astronomical twilight


Astronomical dawn and dusk

Astronomical dawn is the moment when the geometric center of the Sun is 18 degrees below the horizon in the morning. Astronomical dusk is the moment when the geometric center of the Sun is 18 degrees below the horizon in the evening. After astronomical dusk and before astronomical dawn, the sky is not illuminated by the Sun.http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/APN/Gloss-1.pdf#9 Glossary of Marine Navigation


Definition

Morning astronomical twilight begins (astronomical dawn) when the geometric center of the Sun is 18° below the horizon in the morning and ends when the geometric center of the Sun is 12° below the horizon in the morning. Evening astronomical twilight begins when the geometric center of the Sun is 12° below the horizon in the evening and ends (astronomical dusk) when the geometric center of the Sun is 18° below the horizon in the evening. In some places (away from urban
light pollution Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day ...
,
moonlight Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes. Illumination The intensity of moonlight varies greatly depending on the lunar phase, but even the ful ...
,
aurora An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of bri ...
s, and other sources of light), where the sky is dark enough for nearly all astronomical observations, astronomers can easily make observations of point sources such as stars both during and after astronomical twilight in the evening and both before and during astronomical twilight in the morning. However, some critical observations, such as of faint diffuse items such as
nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...
e and
galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...
, may require observation beyond the limit of astronomical twilight. Theoretically, the faintest stars detectable by the naked eye (those of approximately the sixth magnitude) will become visible in the evening at
astronomical dusk Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, eno ...
, and become invisible at
astronomical dawn Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the diffuse sky radiation, appearance of indirect sunlight being Rayleigh scattering, scattered in Earth's atmosphere, when the centre of the Sun's disc h ...
. However, in other places, especially those with
skyglow Skyglow (or sky glow) is the diffuse luminance of the night sky, apart from discrete light sources such as the Moon and visible individual stars. It is a commonly noticed aspect of light pollution. While usually referring to luminance arising f ...
, astronomical twilight may be almost indistinguishable from night. In the evening, even when astronomical twilight has yet to end and in the morning when astronomical twilight has already begun, most casual observers would consider the entire sky fully dark. Because of
light pollution Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day ...
, observers in some localities, generally in and near large cities, may never have the opportunity to view anything but the brightest stars, irrespective of the presence of any twilight at all, nor to experience anything close to a truly dark sky.


Times of occurrence


Between day and night

Observers within 48°34' of the Equator (within 50° of the Equator in May or November, within 57° of the Equator in April or October) and within 72° of the Equator on the equinoxes can view twilight twice each day on every date of the year between astronomical
dawn Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizo ...
, nautical dawn, or civil dawn, and
sunrise Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning. The term can also refer to the entire process of the solar disk crossing the horizon and its accompanying atmospheric effects. Terminology Al ...
as well as between
sunset Sunset, also known as sundown, is the daily disappearance of the Sun below the horizon due to Earth's rotation. As viewed from everywhere on Earth (except the North and South poles), the equinox Sun sets due west at the moment of both the spring ...
and civil dusk, nautical dusk, or astronomical
dusk Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, enou ...
. This also occurs for most observers at higher latitudes on many dates throughout the year, except those around the summer solstice. However, at latitudes closer than 9 degrees (between 81° and 90°) to either Pole, the Sun cannot rise above the horizon nor sink more than 18 degrees below it on the same day on any date, this example of twilight cannot occur because the angular difference between solar noon and solar midnight elevates less than 18 degrees.


Lasting from one day to the next

At latitudes greater than 48°34' North or South, on dates near the summer solstice, twilight can last from sunset to sunrise, since the Sun does not sink more than 18 degrees below the horizon, so complete darkness does not occur even at solar midnight. These latitudes include many densely populated regions of the Earth, including the entire
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
and other countries in
northern Europe The northern region of Europe has several definitions. A restrictive definition may describe Northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other g ...
and even parts of
central Europe Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the area' ...
. * Civil twilight: between 60°34' and 65°44' north or south (between 62° and 67°10' north or south in May or November, between 69° and 74°10' north or south in April or October). In the northern hemisphere, this includes the center of
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
,
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
,
Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
,
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
,
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
and
Shetland Island Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the ...
. In the southern hemisphere this includes parts of the
Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...
and the northern tip of the
Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...
. When ''civil'' twilight lasts all night, this is also referred as a white night. * Nautical twilight: between 54°34' and 60°34' north or south (between 56° and 62° north or south in May or November, between 63° and 69° north or south in April or October). In the northern hemisphere this includes the center of
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
,
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
,
Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, a ...
,
Latvia Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...
,
Lithuania Lithuania (; lt, Lietuva ), officially the Republic of Lithuania ( lt, Lietuvos Respublika, links=no ), is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea. Lithuania ...
, and
Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...
. In the southern hemisphere this includes the southernmost point of
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, and
Ushuaia Ushuaia ( , ) is the capital of Tierra del Fuego, Antártida e Islas del Atlántico Sur Province, Argentina. With a population of nearly 75,000 and a location below the 54th parallel south latitude, Ushuaia claims the title of world's southern ...
in
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. When ''nautical'' twilight lasts all night, this does not constitute a white night. * Astronomical twilight: between 48°34' and 54°34' north or south (between 50° and 56° north or south in May or November, between 57° and 63° north or south in April or October). In the northern hemisphere, this includes the center of
Isle of Man ) , anthem = "O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in Europe ...
,
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
,
Belarus Belarus,, , ; alternatively and formerly known as Byelorussia (from Russian ). officially the Republic of Belarus,; rus, Республика Беларусь, Respublika Belarus. is a landlocked country in Eastern Europe. It is bordered by R ...
,
Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
,
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
,
Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
,
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
,
Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
,
Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...
,
Bellingham, Washington Bellingham ( ) is the most populous city in, and county seat of Whatcom County in the U.S. state of Washington. It lies south of the U.S.–Canada border in between two major cities of the Pacific Northwest: Vancouver, British Columbia (locat ...
,
Orcas Island, Washington Orcas Island () is the largest of the San Juan Islands of the Pacific Northwest, which are in the northwestern corner of San Juan County, Washington. History and naming of the island The name "Orcas" is a shortened form of ''Horcasitas,'' fro ...
,
Vancouver, British Columbia Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...
,
Luxembourg Luxembourg ( ; lb, Lëtzebuerg ; french: link=no, Luxembourg; german: link=no, Luxemburg), officially the Grand Duchy of Luxembourg, ; french: link=no, Grand-Duché de Luxembourg ; german: link=no, Großherzogtum Luxemburg is a small lan ...
,
Guernsey Guernsey (; Guernésiais: ''Guernési''; french: Guernesey) is an island in the English Channel off the coast of Normandy that is part of the Bailiwick of Guernsey, a British Crown Dependency. It is the second largest of the Channel Islands ...
,
Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...
, and
Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...
. In the southern hemisphere this includes the center of
South Georgia and the South Sandwich Islands ) , anthem = "God Save the King" , song_type = , song = , image_map = South Georgia and the South Sandwich Islands in United Kingdom.svg , map_caption = Location of South Georgia and the South Sandwich Islands in the southern Atlantic Oce ...
,
Bouvet Island Bouvet Island ( ; or ''Bouvetøyen'') is an island claimed by Norway, and declared an uninhabited protected nature reserve. It is a subantarctic volcanic island, situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic Ri ...
,
Heard Island The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size ...
,
Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouzet ...
. It also includes
El Calafate El Calafate, also known as ''Calafate'', is a city in Patagonia, Argentina. It is situated on the southern border of Lake Argentino, in the southwest part of the Santa Cruz Province, about northwest of Río Gallegos. The name of the city is deri ...
and
Río Gallegos Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...
in
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
, and
Puerto Natales Puerto Natales is a city in Chilean Patagonia. It is the capital of both the commune of Natales and the province of Última Esperanza, one of the four provinces that make up the Magallanes and Antartica Chilena Region in the southernmost part of C ...
in
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
. When ''astronomical'' twilight lasts all night, this does not constitute a white night.


Between one night and the next

In
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
and
Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...
latitudes in wintertime, the
polar night The polar night is a phenomenon where the nighttime lasts for more than 24 hours that occurs in the northernmost and southernmost regions of Earth. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnig ...
only rarely produces complete darkness for 24 hours each day. This can occur only at locations within 5.5 degrees of latitude of the Pole, and there only on dates close to the
winter solstice The winter solstice, also called the hibernal solstice, occurs when either of Earth's poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere ( Northern and Southern). For that hemisphere, the winte ...
. At all other latitudes and dates, the polar night includes a daily period of twilight, when the Sun is not far below the horizon. Around winter solstice, when the solar declination changes slowly, complete darkness lasts several weeks at the Pole itself, e.g., from May 11 to July 31 at
Amundsen–Scott South Pole Station The Amundsen–Scott South Pole Station is the United States scientific research station at the South Pole of the Earth. It is the southernmost point under the jurisdiction (not sovereignty) of the United States. The station is located on the ...
. North Pole has the experience of this from November 13 to January 29. Solar noon at civil twilight during a polar night: between 67°24' and 72°34' north or south. Solar noon at nautical twilight during a polar night: between 72°34' and 78°34' north or south. Solar noon at astronomical twilight during a polar night: between 78°34' and 84°34' north or south. Solar noon at night during a polar night: between 84°34' and 90° north or south.


Lasting for 24 hours

At latitudes within 9 degrees of either Pole, as the Sun's angular elevation difference is less than 18 degrees, twilight can last for the entire 24 hours. This occurs for one day at latitudes near 9 degrees from the Pole and extends up to several weeks the further toward the Pole one goes. The only permanent settlement to experience this condition is
Alert, Nunavut Alert, in the Qikiqtaaluk Region of Nunavut, Canada, is the northernmost continuously inhabited place in the world, ("Twice a year, the military resupply Alert, the world's northernmost settlement.") on Ellesmere Island (Queen Elizabeth Island ...
, Canada, where it occurs for a week in late February, and again in late October.


Duration

The duration of twilight depends on the latitude and the time of the year. The apparent travel of the Sun occurs at the rate of 15 degrees per hour (360° per day), but sunrise and sunset happen typically at oblique angles to the horizon and the actual duration of any twilight period will be a function of that angle, being longer for more oblique angles. This angle of the Sun's motion with respect to the horizon changes with
latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
as well as the time of year (affecting the angle of the Earth's axis with respect to the Sun). At
Greenwich, England Greenwich ( , ,) is a town in south-east London, England, within the ceremonial county of Greater London. It is situated east-southeast of Charing Cross. Greenwich is notable for its maritime history and for giving its name to the Greenwich ...
(51.5°N), the duration of civil twilight will vary from 33 minutes to 48 minutes, depending on the time of year. At the
equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
, civil twilight can last as little as 24 minutes. This is true because at
low latitudes The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
the Sun's apparent movement is
perpendicular In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle (90 degrees or π/2 radians). The condition of perpendicularity may be represented graphically using the ''perpendicular symbol'', ⟂. It can ...
to the observer's horizon. But at the poles, civil twilight can be as long as 2–3 weeks. In the
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
and
Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...
regions, twilight (if there is any) can last for several hours. There is no astronomical twilight at the poles near the
winter solstice The winter solstice, also called the hibernal solstice, occurs when either of Earth's poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere ( Northern and Southern). For that hemisphere, the winte ...
(for about 74 days at the North Pole and about 80 days at the South Pole). As one gets closer to the Arctic and Antarctic circles, the Sun's disk moves toward the observer's horizon at a lower angle. The observer's earthly location will pass through the various twilight zones less directly, taking more time. Within the
polar circle A polar circle is a geographic term for a conditional circular line (arc) referring either to the Arctic Circle or the Antarctic Circle. These are two of the keynote circles of latitude (parallels). On Earth, the Arctic Circle is currently ...
s, twenty-four-hour daylight is encountered in summer, and in regions very close to the poles, twilight can last for weeks on the winter side of the
equinox A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" and se ...
es. Outside the polar circles, where the angular distance from the polar circle is less than the angle which defines twilight (see above), twilight can continue through local midnight near the
summer solstice The summer solstice, also called the estival solstice or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere ( Northern and Southern). For that hemisphere, the summer ...
. The precise position of the polar circles, and the regions where twilight can continue through local midnight, varies slightly from year to year with Earth's
axial tilt In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbi ...
. The lowest latitudes at which the various twilights can continue through local midnight are approximately 60.561° (60°33′43″) for civil twilight, 54.561° (54°33′43″) for nautical twilight and 48.561° (48°33′43″) for astronomical twilight. These are the largest cities of their respective countries where the various twilights can continue through local solar midnight: * Civil twilight from sunset to sunrise:
Tampere Tampere ( , , ; sv, Tammerfors, ) is a city in the Pirkanmaa region, located in the western part of Finland. Tampere is the most populous inland city in the Nordic countries. It has a population of 244,029; the urban area has a population o ...
,
Umeå Umeå ( , , , locally ; South Westrobothnian: ;). fi, Uumaja; sju, Ubmeje; sma, Upmeje; se, Ubmi) is a city in northeast Sweden. It is the seat of Umeå Municipality and the capital of Västerbotten County. Situated on the Ume River, Ume ...
,
Trondheim Trondheim ( , , ; sma, Tråante), historically Kaupangen, Nidaros and Trondhjem (), is a city and municipality in Trøndelag county, Norway. As of 2020, it had a population of 205,332, was the third most populous municipality in Norway, and ...
,
Tórshavn Tórshavn (; lit. "Thor's harbour"), usually locally referred to as simply ''Havn'', is the capital and largest city of the Faroe Islands. It is located in the southern part on the east coast of Streymoy. To the northwest of the city lies the ...
,
Reykjavík Reykjavík ( ; ) is the capital and largest city of Iceland. It is located in southwestern Iceland, on the southern shore of Faxaflói bay. Its latitude is 64°08' N, making it the world's northernmost capital of a sovereign state. With a po ...
,
Nuuk Nuuk (; da, Nuuk, formerly ) is the capital and largest city of Greenland, a constituent country of the Kingdom of Denmark. Nuuk is the seat of government and the country's largest cultural and economic centre. The major cities from other co ...
,
Whitehorse Whitehorse () is the capital of Yukon, and the largest city in Northern Canada. It was incorporated in 1950 and is located at kilometre 1426 (Historic Mile 918) on the Alaska Highway in southern Yukon. Whitehorse's downtown and Riverdale areas ...
,
Anchorage Anchorage () is the largest city in the U.S. state of Alaska by population. With a population of 291,247 in 2020, it contains nearly 40% of the state's population. The Anchorage metropolitan area, which includes Anchorage and the neighboring Ma ...
,
Arkhangelsk Arkhangelsk (, ; rus, Арха́нгельск, p=ɐrˈxanɡʲɪlʲsk), also known in English as Archangel and Archangelsk, is a types of inhabited localities in Russia, city and the administrative center of Arkhangelsk Oblast, Russia. It lies o ...
and
Baltasound Baltasound (or Baltasund) is the largest settlement on the island of Unst in Shetland, Scotland. It comes from the Old Norse man's name Balti (Baltisund). Unst is the most northerly inhabited island in the United Kingdom. The village lies halfwa ...
. In the Southern Hemisphere, there are no major permanent settlements far enough south to experience this. * Nautical twilight from civil dusk to civil dawn:
Saint Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...
,
Moscow Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 million ...
,
Vitebsk Vitebsk or Viciebsk (russian: Витебск, ; be, Ві́цебск, ; , ''Vitebsk'', lt, Vitebskas, pl, Witebsk), is a city in Belarus. The capital of the Vitebsk Region, it has 366,299 inhabitants, making it the country's fourth-largest ci ...
,
Vilnius Vilnius ( , ; see also other names) is the capital and largest city of Lithuania, with a population of 592,389 (according to the state register) or 625,107 (according to the municipality of Vilnius). The population of Vilnius's functional urb ...
,
Riga Riga (; lv, Rīga , liv, Rīgõ) is the capital and largest city of Latvia and is home to 605,802 inhabitants which is a third of Latvia's population. The city lies on the Gulf of Riga at the mouth of the Daugava river where it meets the Ba ...
,
Tallinn Tallinn () is the most populous and capital city of Estonia. Situated on a bay in north Estonia, on the shore of the Gulf of Finland of the Baltic Sea, Tallinn has a population of 437,811 (as of 2022) and administratively lies in the Harju ' ...
,
Wejherowo Wejherowo ( csb, Wejrowò; german: Neustadt in Westpreußen, formerly Weyhersfrey) is a city in Gdańsk Pomerania, northern Poland, with 48,735 inhabitants (2021). It has been the capital of Wejherowo County in Pomeranian Voivodeship since 199 ...
,
Flensburg Flensburg (; Danish, Low Saxon: ''Flensborg''; North Frisian: ''Flansborj''; South Jutlandic: ''Flensborre'') is an independent town (''kreisfreie Stadt'') in the north of the German state of Schleswig-Holstein. Flensburg is the centre of the ...
,
Helsinki Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and towns in Finland, most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of U ...
,
Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...
,
Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
,
Oslo Oslo ( , , or ; sma, Oslove) is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of in 2022, while the city's greater urban area had a population of ...
,
Newcastle upon Tyne Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is ...
,
Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...
,
Glasgow Glasgow ( ; sco, Glesca or ; gd, Glaschu ) is the most populous city in Scotland and the fourth-most populous city in the United Kingdom, as well as being the 27th largest city by population in Europe. In 2020, it had an estimated popul ...
,
Belfast Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdo ...
,
Letterkenny Letterkenny ( ga, Leitir Ceanainn , meaning 'hillside of the O'Cannons'), nicknamed 'the Cathedral Town', is the largest and most populous town in County Donegal, a county in Ulster, the northern province in Ireland. Letterkenny lies on the R ...
,
Petropavl Petropavl ( kk, Петропавл, Petropavl ) or Petropavlovsk () is a city on the Ishim River in northern Kazakhstan close to the border with Russia. It is the capital of the North Kazakhstan Region. Population: 218,956. The city is also kno ...
,
Nanortalik Nanortalik (), formerly Nennortalik, is a town in Nanortalik Island, Kujalleq municipality, southern Greenland. With 1,185 inhabitants as of 2020, it is the eleventh-largest town in the country. The name ''Nanortalik'' means "Place of Polar Bears ...
,
Grande Prairie Grande Prairie is a city in northwest Alberta, Canada within the southern portion of an area known as Peace River Country. It is located at the intersection of Highway 43 (part of the CANAMEX Corridor) and Highway 40 (the Bighorn Highway), a ...
,
Juneau The City and Borough of Juneau, more commonly known simply as Juneau ( ; tli, Dzánti K'ihéeni ), is the capital city of the state of Alaska. Located in the Gastineau Channel and the Alaskan panhandle, it is a unified municipality and the se ...
,
Ushuaia Ushuaia ( , ) is the capital of Tierra del Fuego, Antártida e Islas del Atlántico Sur Province, Argentina. With a population of nearly 75,000 and a location below the 54th parallel south latitude, Ushuaia claims the title of world's southern ...
, and
Puerto Williams Puerto Williams (; Spanish language, Spanish for "Port Williams") is the city, port and naval base on Navarino Island in Chile. It faces the Beagle Channel. It is the Capital city, capital of Antártica Chilena Province, the Chilean Antarctic Prov ...
. * Astronomical twilight from nautical dusk to nautical dawn:
Hulun Buir Hulunbuir or Hulun Buir ( mn, , ''Kölün buyir'', Mongolian Cyrillic: Хөлөнбуйр, ''Khölönbuir''; zh, s=呼伦贝尔, ''Hūlúnbèi'ěr'') is a region that is governed as a prefecture-level city in northeastern Inner Mongolia, China. ...
,
Erdenet Erdenet ( mn, Эрдэнэт, literally "with treasure") is the third-largest city in Mongolia, with a 2018 population of 98,045, and the capital of the aimag (province) of Orkhon. Located in the northern part of the country, it lies in a valley ...
,
Nur-Sultan Astana, previously known as Akmolinsk, Tselinograd, Akmola, and most recently Nur-Sultan, is the capital city of Kazakhstan. The city lies on the banks of the Ishim (river), Ishim River in the north-central part of Kazakhstan, within the Akmo ...
,
Samara Samara ( rus, Сама́ра, p=sɐˈmarə), known from 1935 to 1991 as Kuybyshev (; ), is the largest city and administrative centre of Samara Oblast. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with ...
,
Kyiv Kyiv, also spelled Kiev, is the capital and most populous city of Ukraine. It is in north-central Ukraine along the Dnieper, Dnieper River. As of 1 January 2021, its population was 2,962,180, making Kyiv the List of European cities by populat ...
,
Minsk Minsk ( be, Мінск ; russian: Минск) is the capital and the largest city of Belarus, located on the Svislach and the now subterranean Niamiha rivers. As the capital, Minsk has a special administrative status in Belarus and is the admi ...
,
Alytus Alytus is a city with municipal rights in southern Lithuania. It is the capital of Alytus County. Its population in 2022 was 53,925. Alytus is the historical centre of the Dzūkija region. The city lies on the banks of the Nemunas River. The maj ...
,
Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...
,
Košice Košice ( , ; german: Kaschau ; hu, Kassa ; pl, Коszyce) is the largest city in eastern Slovakia. It is situated on the river Hornád at the eastern reaches of the Slovak Ore Mountains, near the border with Hungary. With a population of app ...
,
Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
,
Dublin Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...
,
Zwettl __NOTOC__ Zwettl (; Central Bavarian: ''Zwedl''; Czech: ''Světlá'') is a town and district capital of the Austrian state of Lower Austria. It is chiefly known as the location of Zwettl Abbey, first mentioned in October 1139. History The n ...
,
Prague Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 million people. The city has a temperate ...
,
Stanley Stanley may refer to: Arts and entertainment Film and television * ''Stanley'' (1972 film), an American horror film * ''Stanley'' (1984 film), an Australian comedy * ''Stanley'' (1999 film), an animated short * ''Stanley'' (1956 TV series) ...
(Falkland Islands),
Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...
,
Hamburg (male), (female) en, Hamburger(s), Hamburgian(s) , timezone1 = Central (CET) , utc_offset1 = +1 , timezone1_DST = Central (CEST) , utc_offset1_DST = +2 , postal ...
,
Luxembourg City Luxembourg ( lb, Lëtzebuerg; french: Luxembourg; german: Luxemburg), also known as Luxembourg City ( lb, Stad Lëtzebuerg, link=no or ; french: Ville de Luxembourg, link=no; german: Stadt Luxemburg, link=no or ), is the capital city of the Lu ...
,
Brussels Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
,
Amsterdam Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...
,
London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
,
Cardiff Cardiff (; cy, Caerdydd ) is the capital and largest city of Wales. It forms a principal area, officially known as the City and County of Cardiff ( cy, Dinas a Sir Caerdydd, links=no), and the city is the eleventh-largest in the United Kingd ...
,
Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...
,
Calgary Calgary ( ) is the largest city in the western Canadian province of Alberta and the largest metro area of the three Prairie Provinces. As of 2021, the city proper had a population of 1,306,784 and a metropolitan population of 1,481,806, makin ...
,
Unalaska Unalaska ( ale, Iluulux̂; russian: Уналашка) is the chief center of population in the Aleutian Islands. The city is in the Aleutians West Census Area, a regional component of the Unorganized Borough in the U.S. state of Alaska. Unalaska ...
, Bellingham (largest in the continental USA),
Rio Gallegos Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...
, and
Punta Arenas Punta Arenas (; historically Sandy Point in English) is the capital city of Chile's southernmost region, Magallanes and Antarctica Chilena. The city was officially renamed as Magallanes in 1927, but in 1938 it was changed back to "Punta Aren ...
. * Major cities that near astronomical twilight from nautical dusk to nautical dawn:
Khabarovsk Khabarovsk ( rus, Хабaровск, a=Хабаровск.ogg, r=Habárovsk, p=xɐˈbarəfsk) is the largest types of inhabited localities in Russia, city and the administrative centre of Khabarovsk Krai, Russia,Law #109 located from the China ...
(48°29'0"N),
Dnipro Dnipro, previously called Dnipropetrovsk from 1926 until May 2016, is Ukraine's fourth-largest city, with about one million inhabitants. It is located in the eastern part of Ukraine, southeast of the Ukrainian capital Kyiv on the Dnieper Rive ...
(48°27'0"N),
Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...
(48°25'42"N), Saguenay (48°25′0"N),
Brest Brest may refer to: Places *Brest, Belarus **Brest Region **Brest Airport **Brest Fortress *Brest, Kyustendil Province, Bulgaria *Břest, Czech Republic *Brest, France **Arrondissement of Brest **Brest Bretagne Airport ** Château de Brest *Brest, ...
(48°23′26"N),
Thunder Bay Thunder Bay is a city in and the seat of Thunder Bay District, Ontario, Canada. It is the most populous municipality in Northwestern Ontario and the second most populous (after Greater Sudbury) municipality in Northern Ontario; its population ...
(48°22′56″N),
Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...
(48°12′30″N),
Bratislava Bratislava (, also ; ; german: Preßburg/Pressburg ; hu, Pozsony) is the Capital city, capital and largest city of Slovakia. Officially, the population of the city is about 475,000; however, it is estimated to be more than 660,000 — approxim ...
(48°8′38″N),
Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...
(48°8'0"N) Although Helsinki, Oslo, Stockholm, Tallinn, and Saint Petersburg also enter into nautical twilight after sunset, they do have noticeably lighter skies at night during the summer solstice than other locations mentioned in their category above, because they do not go far into nautical twilight. A white night is a night with only civil twilight which lasts from sunset to sunrise. At the winter solstice within the polar circle, twilight can extend through solar noon at latitudes below 72.561° (72°33′43″) for civil twilight, 78.561° (78°33′43″) for nautical twilight, and 84.561° (84°33′43″) for astronomical twilight.


On other planets

Twilight on
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
is longer than on Earth, lasting for up to two hours before sunrise or after sunset. Dust high in the atmosphere scatters light to the night side of the planet. Similar twilights are seen on Earth following major
volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...
s.


In religion


Christianity

In
Christian Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χρι ...
practice, "
vigil A vigil, from the Latin ''vigilia'' meaning ''wakefulness'' (Greek: ''pannychis'', or ''agrypnia'' ), is a period of purposeful sleeplessness, an occasion for devotional watching, or an observance. The Italian word ''vigilia'' has become genera ...
" observances often occur during twilight on the evening before major feast days or holidays. For example, the ''
Easter Vigil Easter Vigil, also called the Paschal Vigil or the Great Vigil of Easter, is a liturgy held in traditional Christian churches as the first official celebration of the Resurrection of Jesus. Historically, it is during this liturgy that people are ba ...
'' is held in the hours of darkness between sunset on
Holy Saturday Holy Saturday ( la, Sabbatum Sanctum), also known as Great and Holy Saturday (also Holy and Great Saturday), the Great Sabbath, Hallelujah Saturday (in Portugal and Brazil), Saturday of the Glory, Sabado de Gloria, and Black Saturday or Easter ...
and sunrise on
Easter Day Easter,Traditional names for the feast in English are "Easter Day", as in the ''Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel P ...
— most commonly in the evening of Holy Saturday or midnight — and is the first celebration of Easter, days traditionally being considered to begin at sunset.


Hinduism

Twilight is sacred in
Hinduism Hinduism () is an Indian religion or '' dharma'', a religious and universal order or way of life by which followers abide. As a religion, it is the world's third-largest, with over 1.2–1.35 billion followers, or 15–16% of the global p ...
. It is called गोधूळिवेळ ''gōdhūḷivēḷ'' in Sanskrit or गोधूलिवेला ''godhūlivelā'' in
Hindi Hindi (Devanāgarī: or , ), or more precisely Modern Standard Hindi (Devanagari: ), is an Indo-Aryan language spoken chiefly in the Hindi Belt region encompassing parts of northern, central, eastern, and western India. Hindi has been de ...
, గొధూళివేళ "godhoolivela" in Telugu, literally "cow dust time". Many
ritual A ritual is a sequence of activities involving gestures, words, actions, or objects, performed according to a set sequence. Rituals may be prescribed by the traditions of a community, including a religious community. Rituals are characterized, b ...
s, including
Sandhyavandanam Sandhyavandanam (Sanskrit: , ', lit. 'salutation to (Goddess) Twilight' or 'salutation during the twilight') is a mandatory religious ritual centring around the recitation of the Gayatri mantra, traditionally supposed to be performed three times ...
and Puja, are performed at twilight hour. Eating of food is not advised during this time. Sometimes it is referred to as Asurasandhya vela. It is believed that
Asura Asuras (Sanskrit: असुर) are a class of beings in Indian religions, Indic religions. They are described as power-seeking clans related to the more benevolent Deva (Hinduism), Devas (also known as Suras) in Hinduism. In its Buddhism, Buddhi ...
s are active during these hours. One of the avatars of Lord
Vishnu Vishnu ( ; , ), also known as Narayana and Hari, is one of the principal deities of Hinduism. He is the supreme being within Vaishnavism, one of the major traditions within contemporary Hinduism. Vishnu is known as "The Preserver" within t ...
,
Narasimha Narasimha ( sa, नरसिंह, lit=man-lion, ), sometimes rendered Narasingha, is the fourth avatar of the Hindu god Vishnu. He is regarded to have incarnated in the form of a part-lion, part-man being to slay Hiranyakashipu, to end rel ...
, is closely associated with the twilight period. According to
Hindu scriptures Hindu texts are manuscripts and voluminous historical literature which are related to any of the diverse traditions within Hinduism. A few of these texts are shared across these traditions and they are broadly considered Hindu scriptures. These ...
, a daemonic king,
Hiranakashipa Hiranyakashipu (; also known as Hiranyakashyap) was an Asura king of the ''daityas'' from the Puranic scriptures of Hinduism. His name literally translates to "clothed in gold" (''hiranya'' "gold" ''kashipu'' "soft cushion"), and is often inte ...
, performed penance and obtained a boon from
Brahma Brahma ( sa, ब्रह्मा, Brahmā) is a Hindu god, referred to as "the Creator" within the Trimurti, the trinity of supreme divinity that includes Vishnu, and Shiva.Jan Gonda (1969)The Hindu Trinity Anthropos, Bd 63/64, H 1/2, pp. 21 ...
that he could not be killed during day or night, neither by human nor animal, neither inside his house nor outside. Lord
Vishnu Vishnu ( ; , ), also known as Narayana and Hari, is one of the principal deities of Hinduism. He is the supreme being within Vaishnavism, one of the major traditions within contemporary Hinduism. Vishnu is known as "The Preserver" within t ...
appeared in a half-man half-lion form (neither human nor animal), ended the life of Hiranakashipa sitting on the doorstep (neither inside nor outside) during twilight (neither day nor night).


Islam

Twilight is important in
Islam Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic religions, Abrahamic Monotheism#Islam, monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God in Islam, God (or ...
as it determines when certain universally obligatory prayers are to be recited. Morning twilight is when morning prayers ('' Fajr'') are done, while evening twilight is the time for evening prayers (''
Maghrib prayer The Maghrib Prayer ( ar, صلاة المغرب ', "sunset prayer") is one of the five mandatory salah (Islamic prayer). As an Islamic day starts at sunset, the Maghrib prayer is technically the first prayer of the day. If counted from midn ...
''). Also during Ramadhan, the time for ''suhoor'' (morning meal before fasting) ends at morning twilight, while fasting ends after sunset. There is also an important discussion in Islamic jurisprudence between "true dawn" and " false dawn".


Judaism

In Judaism, twilight is considered neither day nor night; consequently it is treated as a safeguard against encroachment upon either. It can be considered a
liminal Liminal is an English adjective meaning "on the threshold", from Latin ''līmen'', plural ''limina''. Liminal or Liminality may refer to: Anthropology and religion * Liminality, the quality of ambiguity or disorientation that occurs in the middle ...
time. For example, the twilight of Friday is reckoned as
Sabbath In Abrahamic religions, the Sabbath () or Shabbat (from Hebrew ) is a day set aside for rest and worship. According to the Book of Exodus, the Sabbath is a day of rest on the seventh day, commanded by God to be kept as a holy day of rest, as G ...
eve, and that of Saturday as Sabbath day; and the same rule applies to festival days.


Gallery

File:ChiangKai-shek memorial2009 amk.jpg, View from the Chiang Kai-shek Memorial Hall, at evening civil twilight,
Taipei, Taiwan Taipei (), officially Taipei City, is the capital and a special municipality of the Republic of China (Taiwan). Located in Northern Taiwan, Taipei City is an enclave of the municipality of New Taipei City that sits about southwest of the ...
File:Mountain Moonset.jpg, Morning twilight mountain moonset File:Rainbow Ridge.jpg, Midsummer twilight over Rainbow Ridge,
Landers, California Landers is an unincorporated community in the High Desert region of the Mojave Desert, in San Bernardino County, Southern California. Landers' population, as of 2017, is 2,982 people. Its residents are sometimes referred to as "Landroids"—an ...
. File:Dawn 1.jpg, Clouds begin to glow with colors at nautical dawn, the second stage of twilight, when the Sun is 12 degrees below the horizon. File:Polar-Night Longyearbyen.jpg, Characteristic polar night blue twilight,
Longyearbyen Longyearbyen (, locally lɔ̀ŋjɑrˌbyːən "The Longyear Town") is the world's northernmost settlement with a population greater than 1,000 and the largest inhabited area of Svalbard, Norway. It stretches along the foot of the left bank ...
,
Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
, located at 78° north File:Koh Kut, Thailand, Bang Bao Pier, Twilight.jpg, Nautical twilight in the Gulf of Thailand File:Arambol, Goa, Arambol Beach party late at night, music and dance.jpg, Twilight in Goa, India File:Moscow 2012 Victory Day Parade Rehearsal, Russian Army, Russia.jpg, Early civil twilight in Moscow, Russia


See also

*
Belt of Venus The Belt of Venus (also called Venus's Girdle, the antitwilight arch, or antitwilight) is an atmospheric phenomenon visible shortly before sunrise or after sunset, during civil twilight. It is a pinkish glow that surrounds the observer, extend ...
*
Diffuse sky radiation Diffuse sky radiation is solar radiation reaching the Earth's surface after having been scattered from the direct solar beam by molecules or particulates in the atmosphere. It is also called sky radiation, the determinative process for chan ...
*
Earth's shadow Earth's shadow (or Earth shadow) is the shadow that Earth itself casts through its atmosphere and into outer space, toward the antisolar point. During the twilight period (both early dusk and late dawn), the shadow's visible fringe – sometimes ...
, visible at twilight *
Gloom Gloom is a low level of light which is so dim that there are physiological and psychological effects. Human vision at this level becomes monochrome and has lessened clarity. Optical and psychological effects Light conditions may be considered g ...
*
Green flash The green flash and green ray are meteorological optical phenomena that sometimes occur transiently around the moment of sunset or sunrise. When the conditions are right, a distinct green spot is briefly visible above the Sun's upper limb; ...
*
Polar night The polar night is a phenomenon where the nighttime lasts for more than 24 hours that occurs in the northernmost and southernmost regions of Earth. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnig ...


References


Footnotes


Further reading

*


External links


Twilight Calculator
Compute twilight times.
Twilight time calculator

Formulae to calculate twilight duration
(archived) by Herbert Glarner.
The colors of twilight and sunset

HM Nautical Almanac Office Websurf
Compute twilight times.
Geoscience Australia "Sunrise and sunset times"
Compute twilight times.
An Excel workbook
with VBA functions for twilight (dawn and dusk), sunrise, solar noon, sunset, and solar position (azimuth and elevation) b

translated fro


Time and Date
to find the current state of the sun in a specified place. {{Authority control Earth phenomena Night Dawn Parts of a day Visibility