Climate of Atlanta
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The Geography of Atlanta encompasses , of which is land and is water. The city is situated among the foothills of the
Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...
, and at above mean sea level, Atlanta has the highest elevation among major cities east of the Mississippi River. Atlanta straddles the
Eastern Continental Divide The Eastern Continental Divide, Eastern Divide or Appalachian Divide is a hydrographic divide in eastern North America that separates the easterly Atlantic Seaboard watershed from the westerly Gulf of Mexico watershed. The divide nearly span ...
, such that rainwater that falls on the south and east side of the divide flows into the Atlantic Ocean, while rainwater on the north and west side of the divide flows into the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
. Atlanta sits atop a
ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...
south of the
Chattahoochee River The Chattahoochee River forms the southern half of the Alabama and Georgia border, as well as a portion of the Florida - Georgia border. It is a tributary of the Apalachicola River, a relatively short river formed by the confluence of the Chatta ...
, which is part of the
ACF River Basin The ACF River Basin is the drainage basin, or watershed, of the Apalachicola River, Chattahoochee River, and Flint River, in the Southeastern United States. This area is alternatively known as simply the Apalachicola Basin and is listed by t ...
. Located at the far northwestern edge of the city, much of the river's natural habitat is preserved, in part by the
Chattahoochee River National Recreation Area Chattahoochee River National Recreation Area (CRNRA) preserves a series of sites between Atlanta and Lake Sidney Lanier along the Chattahoochee River in Georgia, U.S. The 48-mile (77 km) stretch of the river affords public recreation opportu ...
.


Climate

The climate of Atlanta and its metropolitan area is humid subtropical (''Cfa'') according to the Köppen classification, with four
season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and pol ...
s including hot, humid summers and cool winters that are occasionally cold by the standards of the southern United States; the city and its immediate suburbs are located in
USDA Plant Hardiness Zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most wide ...
8a, although the far northern suburbs begin to transition to Zone 7b. Summers are long and consistently hot and humid. The daily average temperature in July is , with temperatures occasionally exceeding , and slight breezes, and typically a 20–40% chance of afternoon
thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are someti ...
s. During the summer afternoon thunderstorms, temperatures may suddenly drop below with locally heavy rainfall. January averages , with temperatures in the suburbs slightly cooler. Warm, maritime air can bring springlike conditions while strong Arctic air masses can push lows to between . Snow may not occur in every season in the city and inner suburbs but does every season in the northern metro. When snow falls it is almost always during the period of December through March: there have occurred only three measurable falls outside these months in the past ninety years, the largest being on November 11, 1968. Typical of the southeastern U.S., Atlanta receives abundant rainfall, which is relatively evenly distributed throughout the year, though spring and early fall are markedly drier. Average annual rainfall is about , with late winter and early spring (as well as July) being the wettest and fall (especially October) being the driest. Despite having far fewer rainy days, average yearly rainfall is higher here than in the
Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...
area, especially due to heavy thunderstorms and occasional
tropical depression A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
s.


Extremes

Temperatures at or above now occur on 44 days per year (up from 37 previously); though there have been as many as 91 days in 2019, and as few as 2 days in 1967. Overnight freezes can be expected on 40 days, but the high temperature rarely fails to climb above the freezing mark. In very cold winter months with high-latitude blocking, averages can occasionally fall below freezing: the coldest month was January 1977 which averaged and which amazingly saw Atlanta average colder than
Anchorage, Alaska 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 ...
, almost 30 degrees latitude further north. The only other month with a subfreezing mean has been January 1940 with an average of and a record cold mean maximum of . Snowfall averages per season. The heaviest single storm brought on January 23, 1940, the most snow in one calendar day, and the most in a calendar month; the most snowfall in a season (July 1 through June 30 of the next year) is in 1935–36. True blizzards are rare but possible; the
Storm of the Century ''Storm of the Century'', alternatively known as ''Stephen King's Storm of the Century'', is a 1999 American horror television miniseries written by Stephen King and directed by Craig R. Baxley. Unlike many other television adaptations of King' ...
, which affected the region on March 12–14, 1993, is one such example, bringing snowdrifts up to high in some parts of north Georgia.
Ice storm An ice storm, also known as a glaze event or a silver storm is a type of winter storm characterized by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of ice on ex ...
s usually cause more trouble than does snowfall; the most severe such storms may have occurred on January 7, 1973, and January 9, 2011. In 2010, Atlanta had its first White Christmas since 1882 and 1883. Later that same winter (the third-coldest ever), a major snow-and-ice storm almost prevented the
inauguration In government and politics, inauguration is the process of swearing a person into office and thus making that person the incumbent. Such an inauguration commonly occurs through a formal ceremony or special event, which may also include an inaugu ...
of the new
governor of Georgia The governor of Georgia is the head of government of Georgia and the commander-in-chief of the state's military forces. The governor also has a duty to enforce state laws, the power to either veto or approve bills passed by the Georgia Legisl ...
, and crippled the region for two days, with snow still left more than a week later in some places. Official weather recordkeeping began in Atlanta in 1878, on the morning of October 3. Since then, the highest recorded temperatures at Atlanta were on June 30, 2012; the hottest month on record is August 2007, with a mean temperature of . The lowest recorded temperatures were and on January 20 and 21 of 1985, and on February 13, 1899. There was also an official recording of in 1985 in
Marietta Marietta may refer to: Places in the United States *Marietta, Jacksonville, Florida *Marietta, Georgia, the largest US city named Marietta *Marietta, Illinois *Marietta, Indiana *Marietta, Kansas *Marietta, Minnesota *Marietta, Mississippi *Mar ...
. The coldest high temperature was , again on February 13, 1899, while, conversely, the hottest low temperature was on August 8, 2007. The rainiest month ever was July 1994, when Tropical Storm Alberto dumped massive amounts of rain on parts of the state and the south metro area, bringing at Atlanta, over three times a normal July. Flooding was a major problem in those areas, and further down-state it was a major disaster. The driest month was October 1963 when a record dry spell occurred over the entire eastern and southern United States, leaving Atlanta with only a trace of precipitation for the entire month.


Data


Effect on vegetation

Some palm trees like palmetto and cacti like prickly pear can withstand the cold nights, complementing numerous flowering
pansies The garden pansy (''Viola'' × ''wittrockiana'') is a type of large-flowered hybrid plant cultivated as a garden flower. It is derived by hybridization from several species in the section ''Melanium'' ("the pansies") of the genus ''Viola'', p ...
and a few
camellia ''Camellia'' (pronounced or ) is a genus of flowering plants in the family Theaceae. They are found in eastern and southern Asia, from the Himalayas east to Japan and Indonesia. There are more than 220 described species, with some controversy ...
s, and other mild-winter-friendly plants of the region. The
growing season A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. Whil ...
in the area lasts several months, hardy plants being as early as mid February, and others from mid March to late October, when the last and first
cold snap A cold wave (known in some regions as a cold snap, cold spell or Arctic Snap) is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in tem ...
s usually occur. Spring weather is pleasant but variable, as cold fronts often bring strong or severe thunderstorms to almost all of the eastern and central U.S.
Pollen count A pollen count is the measurement of the number of grains of pollen in a cubic meter of air. High pollen counts can sometimes lead to increased rates of allergic reaction for those with allergic disorders. Usually, the counts are announced for sp ...
s tend to be extraordinarily high in the spring, regularly exceeding 2000 particles per cubic meter in April and causing
hay fever Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...
, sometimes even in people not normally prone to it. Pine pollen leaves a fine yellow-green film on everything for much of that month. The rain helps wash out Atlanta's abundant oak, pine, and grass pollens, and fuels beautiful blooms from native flowering dogwood trees, as well as
azalea Azaleas are flowering shrubs in the genus ''Rhododendron'', particularly the former sections ''Tsutsusi'' (evergreen) and '' Pentanthera'' (deciduous). Azaleas bloom in the spring (April and May in the temperate Northern Hemisphere, and Octob ...
s,
forsythia ''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is ...
s,
magnolia ''Magnolia'' is a large genus of about 210 to 340The number of species in the genus ''Magnolia'' depends on the taxonomic view that one takes up. Recent molecular and morphological research shows that former genera ''Talauma'', ''Dugandiodendro ...
s, and
peach The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-fu ...
trees (both flowering-only and fruiting). The citywide floral display runs during March and April, and inspires the
Atlanta Dogwood Festival The Atlanta Dogwood Festival is an arts and crafts festival held each spring at Piedmont Park in Atlanta, Georgia, established in 1933. Originally held for nine days across two weekends and the weekdays between, it is now held only one weekend du ...
, one of Atlanta's largest. Fall is also pleasant, with less rain and fewer storms, and leaves changing color from late October to mid-November, especially during drier years. A secondary peak in severe storms also occurs around the second week of November.


Effect of geography

The area's geography affects the weather as well. An
anticyclone An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from abov ...
over the
Northeastern U.S. The Northeastern United States, also referred to as the Northeast, the East Coast, or the American Northeast, is a geographic region of the United States. It is located on the Atlantic coast of North America, with Canada to its north, the Southe ...
will blow cold air over the warmer
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
, forming a wedge or
marine layer A marine layer is an air mass that develops over the surface of a large body of water, such as an ocean or large lake, in the presence of a temperature inversion. The inversion itself is usually initiated by the cooling effect of the water on th ...
up against the mountains. This east or northeast
wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...
will often blow down into the metro area in winter or even spring (sometimes fall and very rarely summer), dramatically lowering the temperature and bringing
cloud In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may co ...
s and often
fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influ ...
or
mist Mist is a phenomenon caused by small droplets of water suspended in the cold air, usually by condensation. Physically, it is an example of a dispersion. It is most commonly seen where water vapor in warm, moist air meets sudden cooling, such a ...
, along with a swift breeze. The temperature
gradient In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gradi ...
across the sprawling metro Atlanta can be as much as 20 °F or 10 °C, occasionally even more. In winter this can be a curse, bringing freezing rain to exposed objects on the north and/or east sides of town, and occasionally very dangerously to the ground and roads. Later in the spring however, it can be a great blessing, as it often protects the area from severe thunderstorms and
tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...
es, with the cool air acting like a fire extinguisher to the storms. The wedge may occasionally go the entire way through central Georgia and even into Alabama in the strongest conditions, while still leaving areas of
northwest Georgia Northwest Georgia is a region of the state of Georgia in the United States. It includes 12 counties (listed in the section below), which at the 2010 census had a combined population of 753,032. Northwest Georgia includes some of the southernmos ...
much warmer than the metro area. Conversely, shallow and heavy cold air from the northwest may be blocked by the mountains, preventing snow. The local geography also plays a role in the day-to-day weather, with the shallow
valley A valley is an elongated low area often running between Hill, hills or Mountain, mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers ...
s to the southwest (rather than the mountains to the northeast) cooling rapidly on clear and calm
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 ...
s, particularly when the
humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...
is low. Peachtree City and especially Newnan often report dramatically lower temperatures (by as much as ) on the 10 pm and 11 pm news, and will not drop much further, while the city (built on a
ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...
) will continue falling slowly but never reach that low. This type of dramatic difference in
microclimate A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few squ ...
is somewhat unusual for a place not near large mountains or bodies of water.


Extreme weather


Tropical cyclones

Hurricane Opal brought sustained
tropical storm A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
conditions to the area one night in early October 1995, uprooting hundreds of
tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s (mainly
oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
s) and causing widespread power outages, after soaking the area with rain for two days prior. The western metro area caught the worst of the storm, gusting to nearly officially at Marietta. Such events are very rare so far inland, some inland from the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
where most of the storms come from; however some areas particularly east and south of the city received similar damage from the wide wind field of Hurricane Irma in September 2017, with a gust to at Atlanta's airport and sustained winds up to there. Record-cool high temperatures of caused by
cold-air damming Cold air damming, or CAD, is a meteorological phenomenon that involves a high-pressure system (anticyclone) accelerating equatorward east of a north-south oriented mountain range due to the formation of a barrier jet behind a cold front associated ...
against the Appalachians served to eliminate the normal tornado risk in north Georgia and to weaken the storm faster than expected, reducing the anticipated damage to the area. Less than a month later in early October 2017, the much smaller Hurricane Nate was forecast to pass rapidly through
northwest Georgia Northwest Georgia is a region of the state of Georgia in the United States. It includes 12 counties (listed in the section below), which at the 2010 census had a combined population of 753,032. Northwest Georgia includes some of the southernmos ...
as a weak tropical storm, expected to cause far fewer issues to the metro area than Irma. These two storms caused the first
tropical storm watch Tropical cyclone warnings and watches are alerts issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local popul ...
es (and for Irma, warnings) for the area since these were allowed to be issued for inland locations instead of just coastal ones.


Tornadoes

Since 1950, some metro counties have been hit more than 20 times by tornadoes, with Cobb (26) and Fulton (22) being two of the highest in the state. (Note that some tornadoes may have occurred at the same time, or in two different counties.) Another struck the
Georgia Governor's Mansion The Governor's Mansion is the official home of the governor of the U.S. state of Georgia. The mansion is located at 391 West Paces Ferry Road NW, in the Tuxedo Park neighborhood of the affluent Buckhead district of Atlanta. Construction The ...
in 1975. The Dunwoody tornado in early April 1998 was the worst
tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...
to have struck the suburban area. Since then, many counties have reinstalled
civil defense siren A civil defense siren, also known as an air-raid siren or tornado siren, is a siren used to provide an emergency population warning to the general population of approaching danger. It is sometimes sounded again to indicate the danger has pas ...
s removed after the
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
. On March 14, 2008, an
EF2 Elongation factors are a set of proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide. Most common elongation ...
tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...
hit downtown Atlanta with winds up to . The tornado caused damage to
Philips Arena State Farm Arena (formerly Philips Arena) is a multi-purpose arena located in Atlanta, Georgia. The arena serves as the home venue for the National Basketball Association (NBA)'s Atlanta Hawks. It also served as home to the National Hockey Leag ...
, the Westin Peachtree Plaza Hotel, the Georgia Dome,
Centennial Olympic Park Centennial Olympic Park is a public park located in downtown Atlanta, Georgia, owned and operated by the Georgia World Congress Center Authority. It was built by the Atlanta Committee for the Olympic Games (ACOG) as part of the infrastructu ...
, the
CNN Center The CNN Center in Atlanta, Georgia, is the international headquarters of the Cable News Network (CNN). The main newsrooms and studios for several of CNN's news channels are located in the building. The facility's commercial office space is occu ...
, and the Georgia World Congress Center. It also damaged the nearby neighborhoods of Vine City to the west and Cabbagetown, and Fulton Bag and Cotton Mills to the east. While there were dozens of injuries, only one fatality was reported. City officials warned it could take months to clear the devastation left by the tornado.


Winter storms

The area experiences a
winter storm A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental climates, these storms are not necessar ...
with significant
snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...
fall about once each year, however this can be extremely irregular. During the 2000s, only four major snows occurred (December 2000, January 2002, January 2008, and March 2009), while three occurred in early 2010 (an El Niño year) alone, making it the snowiest winter since the 1970s. Despite predictions of a warm and dry winter due to
La Niña La Niña (; ) is an oceanic and atmospheric phenomenon that is the colder counterpart of as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name ''La Niña'' originates from Spanish for "the girl", by an ...
developing the following summer, additional fell on December 25, giving the city (and its northern and western suburbs) its first true white Christmas in over a century. The only other measurable snows on that date were in 1881, and in 1882. A trace last fell on
Christmas Christmas is an annual festival commemorating Nativity of Jesus, the birth of Jesus, Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people Observance of Christmas by country, around t ...
in 1993, and a dozen other years before that. A blizzard (see:
1993 Storm of the Century The 1993 Storm of the Century (also known as the 93 Superstorm, The No Name Storm, or the Great Blizzard of '93/1993) was a cyclonic storm that formed over the Gulf of Mexico on March 12, 1993. The cold weather, heavy snowfall, high winds and st ...
) caught much of the Southeast off-guard in 1993, dumping at the Atlanta airport on March 13, and much more than that in the suburbs to the north and west, as well as in the mountains. Dallas, a suburb about to the west-northwest, received from the storm. Some people were awakened by thunder and
lightning Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...
in a very rare thundersnow event. Several areas of northern Cobb County recorded over in snowdrifts. It is widely regarded as the snow event of the century for Atlanta, and is referred to as the "Storm of the Century", placing fifth in the city's snowfall records. The only other recorded winter storm of comparable severity was the Great Blizzard of 1899, which struck in February. A blizzard hit on January 9–15 crippling the city and leaving schools out for the whole week. Ice-covered roads and over eight inches of snow fell in some places with over a foot in the far northern metropolitan area. The heaviest snow, however, was on January 23, 1940, when buried the city during its second-coldest month on record. The second-heaviest was in 1983, when a very late storm dumped on March 24. The latest snow and freeze ever were in 1910, when and were recorded on April 25. Since 1928, the earliest measurable snows were November 11 and 23, followed in 2013 by on the 27th, the day before the second-coldest
Thanksgiving Thanksgiving is a national holiday celebrated on various dates in the United States, Canada, Grenada, Saint Lucia, Liberia, and unofficially in countries like Brazil and Philippines. It is also observed in the Netherlander town of Leiden and ...
on record. Prior to March 2009, the most recent major snow occurred at the beginning of 2002, when up to fell on January 2–3. As of 2007, the stretch of five nearly or entirely snowless winters made for an extremely long period compared to average. This streak was ended in January 2008 when fell on January 16 and fell three days later. The following year, the first widespread
winter storm A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental climates, these storms are not necessar ...
since 2002 dumped on March 1, with the heaviest to the southwest and east-northeast, and surprisingly little or nothing in the far northern suburbs and mountains. Much of it melted almost as fast as it was accumulating at mid-day, while eastern areas had thundersnow and cloud-to-ground strikes reported by lightning detection; it was an upper-level low from the
Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...
, while most major storms in the area occur with a typical surface low-pressure area traveling along the
Gulf A gulf is a large inlet from the ocean into the landmass, typically with a narrower opening than a bay, but that is not observable in all geographic areas so named. The term gulf was traditionally used for large highly-indented navigable bodie ...
coast. The 2009 snow tied with the 1993 blizzard and another storm for fifth-heaviest official daily snow in the city's recorded weather history. Areas to the due east and west often receive more snow than metro Atlanta, because the energy begins to transfer to a coastal low in the Atlantic, on its way to becoming a
nor'easter A nor'easter (also northeaster; see below), or an East Coast low is a synoptic-scale extratropical cyclone in the western North Atlantic Ocean. The name derives from the direction of the winds that blow from the northeast. The original use o ...
. Also the mountains to the northwest entrap shallow cold air. Average annual snowfall from 1971 to 2000 in Atlanta is – the snowiest month is January with . Due to two record-breaking heavy storms during the averaged period, it is actually March that is statistically second with – cut in half if the heaviest storm is removed. This is followed by February with and December with , then November, April, and October averaging a trace each. The latest was April 25, when fell in 1910, also the heaviest for the month, and the latest-ever freeze. Four other April snows have been recorded since 1879, the most recent significant one being April 3, 1987. Flurries occurred in 1993 on the afternoon of
Halloween Halloween or Hallowe'en (less commonly known as Allhalloween, All Hallows' Eve, or All Saints' Eve) is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Saints' Day. It begins the observanc ...
, marking only the third recorded October snow (all of which were an unmeasurable trace). Although December is just as cold as February and has more days, it receives the least snow of any winter month (roughly once per decade), due to less overall precipitation in the later months of the year compared to the rainier mid and late winter. However, the lowest sun and shortest days of the year mean that what does fall can stay around for days. A mid-December 2000 snow (a record for the month) was followed by very cold weather that left spots of it on the ground in shady areas until
Christmas Christmas is an annual festival commemorating Nativity of Jesus, the birth of Jesus, Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people Observance of Christmas by country, around t ...
. Following the 2010 snow, the next December event was in 2017, when the heaviest snows since the March 1993 blizzard hit the northwestern suburbs and west-northwestern exurbs. Paulding, northwest Cobb, and southeast Bartow counties were hit with up to of very heavy and wet snow, due to the temperature being slightly above freezing for much of the event. The very high water content and lack of any wind in turn caused widespread power outages as major accumulations brought down power lines, leaving some without electricity for days. This was the earliest in the season that the metro area is known to have received so much snow, though long-term official records are only kept at Atlanta proper.
Ice storm An ice storm, also known as a glaze event or a silver storm is a type of winter storm characterized by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of ice on ex ...
s have also occurred in the area. Two hit the city a week apart in January 2000, the second one while Atlanta was hosting Super Bowl XXXIV, which was felt to affect the city's future chances for hosting it again. The well-remembered January 1973 ice storm was brutal, and was followed in February by the record-breaking 1973 Southeast U.S. snowstorm that hit the coastal half of the state, bringing light snow to what were then the far southeastern suburbs. A January 1982 snowstorm, which came to be called "Snow Jam '82" by the media and those who lived through it, also crippled the city just as bad as ice can, striking in the afternoon while everyone was at work, several hours earlier than expected. Tens of thousands of people were stranded in the city, abandoning cars on every road and
freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...
and booking
hotel A hotel is an establishment that provides paid lodging on a short-term basis. Facilities provided inside a hotel room may range from a modest-quality mattress in a small room to large suites with bigger, higher-quality beds, a dresser, a ref ...
s to capacity, unable to get home to the suburbs. Despite this well-known experience, the same thing happened in January 2014, when snow expected to hit mainly
middle Georgia Central Georgia is the area containing the metropolitan region surrounding the city of Macon, in Bibb County in the U.S. state of Georgia. It abuts the Atlanta metropolitan area, just to the north. Similar and coextensive names for this region ...
in the afternoon crept northward at midday, the resulting road ice stranding children in schools and even on
school bus A school bus is any type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to transport students to and from school or school-related activities, but not including a charter bus or transit bus ...
es overnight, while people slept in makeshift shelters such as
Home Depot The Home Depot, Inc., is an American multinational corporation, multinational home improvement retail corporation that sells tools, construction products, appliances, and services, including fuel and transportation rentals. Home Depot is the l ...
, Kroger, and
CVS CVS may refer to: Organizations * CVS Health, a US pharmacy chain ** CVS Pharmacy ** CVS Caremark, a prescription benefit management subsidiary * Council for Voluntary Service, England * Cable Video Store, former US pay-per-view service * CVS F ...
stores, and in fire stations and even in their vehicles. Commutes that normally take minutes instead took several hours or even until the next day, with average speeds near zero and many vehicles running out of
gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
. Several people simply walked to their destination, while Georgia National Guard troops were called to join
HERO A hero (feminine: heroine) is a real person or a main fictional character who, in the face of danger, combats adversity through feats of ingenuity, courage, or Physical strength, strength. Like other formerly gender-specific terms (like ...
units along with the Georgia State Patrol and local police in checking on stuck and abandoned cars. While only fell on the afternoon of the 28th, and many issues from the 2011 snow-then-ice storm had been addressed, the sudden rush of traffic between noon and 1pm rapidly created massive
gridlock Gridlock is a form of traffic congestion where "continuous queues of vehicles block an entire network of intersecting streets, bringing traffic in all directions to a complete standstill". The term originates from a situation possible in a grid ...
and prevented
snow removal Snow removal or snow clearing is the job of removing snow after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions. De-icing and anti-icing De-icing is defined as removal ...
and deicing equipment from going anywhere. GDOT equipment that had been dispatched to areas further down-state based on early forecasts also lessened the response, as they could not get back north to their regular districts in time. Officials tried to blame the
National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...
, but this was refuted by The Weather Channel,
CNN CNN (Cable News Network) is a multinational cable news channel headquartered in Atlanta, Georgia, U.S. Founded in 1980 by American media proprietor Ted Turner and Reese Schonfeld as a 24-hour cable news channel, and presently owned by the M ...
, and local TV stations, which showed that
winter storm warning A winter storm warning ( SAME code: WSW) is a hazardous weather statement issued by Weather Forecast Offices (WFO) of the National Weather Service (NWS) in the United States to alert the public that a winter storm is occurring or is about to occur ...
s were extended up to the northern suburbs more than two hours before most
school system State schools (in England, Wales, Australia and New Zealand) or public schools (Scottish English and North American English) are generally primary or secondary educational institution, schools that educate all students without charge. They are ...
s needed to decide on whether to cancel school for the day, and even the prior
winter weather advisory A winter weather advisory (originally identified as a Traveler's Advisory until the 2002-03 climatological winter when officially renamed, and informally as such by some local television stations thereafter) is a hazardous weather statement issued ...
should have been enough to cause these cancellations.


Drought

The driest year in Atlanta history was 1954 (31 inches of rain), with 2007 being a close second. The Southeastern U.S. drought of 2006–2008 began with dry weather in 2006, and left area
lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s very low. Most of the area's
drinking water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
is stored in Lake Lanier and
Lake Allatoona Lake Allatoona (officially called Allatoona Lake) is a U.S. Army Corps of Engineers reservoir on the Etowah River in northwestern part of the State of Georgia. This reservoir is mostly in southeastern Bartow County and southwestern Cherokee Coun ...
, which reached record low levels in December 2007. Up through September 2007 was the driest year on record in over 75 years, second only to 1927 and 1931. On September 28, the state issued a total outdoor watering ban for the north and northwestern 40% or so of the state, affecting 61 counties generally north of the
Fall Line A fall line (or fall zone) is the area where an upland region and a coastal plain meet and is typically prominent where rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the coa ...
. (Some local authorities and
water system A water supply network or water supply system is a system of engineered hydrologic and hydraulic components that provide water supply. A water supply system typically includes the following: # A drainage basin (see water purification – source ...
s had already taken such measures.) It was the first time the state had enacted such a ban. Throughout the 3-year drought the Atlanta area occasionally experienced smoke from the wildfires in south Georgia, causing the local air to become dangerous for everyone. The severe record
drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, an ...
which affected the region starting in late 2006 finally began to abate significantly after heavy fall rains in 2009.


Flooding

The historic drought ended with historic flooding in 2009. The
2009 Atlanta floods The September 2009 Southeastern United States floods were a group of floods that affected several counties throughout northern Georgia, Tennessee, Alabama, Mississippi, and Arkansas. The worst flooding occurred across the Atlanta metropolitan area ...
affected the entire area on September 21, 2009, with parts of eastern Paulding, northern Douglas, and southwestern Cobb counties getting around of rain in a week, with half of that falling in just 24 hours near the end of the period.
Douglasville The city of Douglasville is the county seat of Douglas County, Georgia, Douglas County, Georgia (U.S. state), Georgia, United States. , the city had a population of 34,650, up from 30,961 in 2010 United States census, 2010 and 20,065 in 2000 Uni ...
received the most rain in 24 hours than any other city in metro Atlanta, the city received over 16.5 inches of rain on Sept 21, 2009. (The
USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...
calculated it to be a greater-than-
500-year flood A 100-year flood is a flood event that has a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 100-year flood is also referred to as the 1% flood, since its annual exceedance probability is 1%.Holmes, R.R., Jr. ...
; the
National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...
stated that chances of that much rain anywhere in the region are 1 in 10,000 years.) Some freeways closed temporarily, and several small bridges and
culvert A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe, reinforced concrete or other material. In the United Kingdom ...
s were ruined and will take months to replace. Many homes in the area were completely destroyed. Occasional heavy rains and flood advisories continued through early February 2010. Flood events are localized from nearly stationary thunderstorms, or more broadly impacting from slow-moving tropical storm remnants, or sometimes from unusually heavy and persistent winter rains during El Niño years. Other droughts have also ended in lesser floods, including in 1989. The flooding has also ended as of 2010.


Environmental issues

In 2007, the American Lung Association ranked Atlanta as having the 13th highest level of particle pollution in the United States. The combination of pollution and pollen levels, and uninsured citizens caused the Asthma and Allergy Foundation of America to name Atlanta as the worst American city for asthma sufferers to live in. However in 2010, all counties in the Atlanta metro area began requiring yearly emissions testing for all motor vehicles, with the exception of antique cars and the three most recent model years. Bright spots include projects that encourage
smart growth Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl. It also advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood sch ...
, such as the
BeltLine The Atlanta BeltLine (also Beltline or Belt Line) is a open and planned loop of multi-use trail and light rail transit system on a former railway corridor around the core of Atlanta, Georgia. The Atlanta BeltLine is designed to reconnect neig ...
and Atlantic Station
mixed-use development Mixed-use is a kind of urban development, urban design, urban planning and/or a zoning type that blends multiple uses, such as residential, commercial, cultural, institutional, or entertainment, into one space, where those functions are to some ...
, which the
Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
commended in 2005. In 2009, Atlanta's Virginia-Highland became the first
carbon-neutral Carbon neutrality is a state of net-zero carbon dioxide emissions. This can be achieved by balancing emissions of carbon dioxide with its removal (often through carbon offsetting) or by eliminating emissions from society (the transition to the "p ...
zone in the United States. There, neighborhood merchants, through the Chicago Climate Exchange, directly fund the Valley Wood Carbon Sequestration Project (thousands of acres of forest in rural Georgia).


Notes


References


External links


Atlanta City Limits in 1952
{{Metro Atlanta