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A semi-arid climate, semi-desert climate, or steppe climate is the
climate Climate is the long-term pattern of weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena ...

climate
of a region that receives precipitation below
potential evapotranspiration Evapotranspiration (ET) is the sum of water evaporation File:10. Ладење при испарување.ogv, 280px, Demonstration of evaporative cooling. When the sensor is dipped in ethanol and then taken out to evaporate, the instrument sh ...
, but not as low as a
desert climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a climate which there is an excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert climates hold little mo ...
. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different
biomes A biome is a collection of flora, plants and fauna, animals that have common characteristics for the natural environment, environment they exist in. They can be found over a range of continents. Biomes are distinct biological community (ecology) ...
.


Defining attributes of semi-arid climates

A more precise definition is given by the
Köppen climate classification The Köppen climate classification is one of the most widely used systems. It was first published by German-Russian (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist (1894- ...
, which treats
steppe File:Steppe of western Kazakhstan in the early spring.jpg, Steppe in Kazakhstan In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes. Steppe biomes may ...

steppe
climates (''BSk'' and ''BSh'') as intermediates between
desert climate The desert climate or arid climate (in the Köppen climate classification ''BWh'' and ''BWk''), is a climate which there is an excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert climates hold little mo ...
s (BW) and humid climates in ecological characteristics and agricultural potential. Semi-arid climates tend to support short or scrubby vegetation and are usually dominated by either
grass Poaceae () or Gramineae () is a large and nearly ubiquitous family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain ...

grass
es or
shrub A shrub (often called a bush) is a small- to medium-sized perennial A perennial plant or simply perennial is a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the p ...

shrub
s. To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. The method used to find the precipitation threshold (in millimeters): *multiply by 20 the average annual temperature in degrees Celsius and then **add 280 if at least 70% of the total precipitation falls in the high-sun half of the year (April–September in the northern hemisphere, October–March in the southern hemisphere) **add 140 if 30–70% of the total precipitation falls in the high-sun half of the year **add nothing if less than 30% of the total precipitation falls in the high-sun half of the year If the area's annual precipitation in millimeters is less than the threshold but more than half the threshold, it is classified as a ''BS'' (steppe or semi-arid climate). Furthermore, to delineate hot semi-arid climates from cold semi-arid climates, there are three widely used isotherms: either a mean annual temperature of , a mean temperature of in the coldest month, or a mean temperature of in the coldest month. A location with a ''BS''-type climate is classified as hot semi-arid (''BSh'') if its appropriate mean temperature is above whichever isotherm is being used, and a location with temperature below the given isotherm is classified as cold semi-arid (''BSk'').


Hot semi-arid climates

Hot semi-arid climates (type "BSh") tend to be located in the 20s and 30s latitudes of the (
tropics The tropics are the region of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% i ...

tropics
and
subtropics The subtropical zones or subtropics are geographical Geography (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country locat ...

subtropics
), typically in proximity to regions with a
tropical savanna Tropical and subtropical grasslands, savannas, and shrublands is a terrestrial biome defined by the World Wide Fund for Nature The World Wide Fund for Nature (WWF) is an international non-governmental organization founded in 1961 that wor ...
or a
humid subtropical climate A humid subtropical climate is a zone of climate characterized by hot and humid summers, and cool to mild winters. These climates normally lie on the southeast side of all continents, generally between latitude In geography Geograp ...
. These climates tend to have hot, sometimes extremely hot, summers and warm to cool winters, with some to minimal precipitation. Hot semi-arid climates are most commonly found around the fringes of subtropical deserts. Hot semi-arid climates are most commonly found in
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area and 20% of i ...

Africa
,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
and
South Asia South Asia is the southern region of Asia, which is defined in both geography, geographical and culture, ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri La ...

South Asia
. In Australia, a large portion of the
Outback The Outback is a vast, sparsely populated area of Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the isl ...

Outback
surrounding the central desert regions lies within the hot semi-arid climate region.Bureau of Meteorology - climate classification maps
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India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

India
and sections of
Pakistan Pakistan, . Pronounced variably in English as , , , and . officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a popul ...

Pakistan
experience the seasonal effects of
monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation In meteorology Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric ph ...

monsoon
s and feature short but well-defined wet seasons, but are not sufficiently wet overall to qualify as a
tropical savanna climate Tropical savanna climate or tropical wet and dry climate is a type of climate Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it is the mean and variability of meteorological variables ...
. Hot semi-arid climates can also be found in
Europe Europe is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered ...

Europe
, primarily in southeast
Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = , national_anthem = , image_map = , map_caption = , image_map2 ...

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http://www.aemet.es/documentos/es/conocermas/recursos_en_linea/publicaciones_y_estudios/publicaciones/2Atlas_climatologico/Atlas_Clima_Macaronesia___Baja.pdf and parts of
Greece Greece ( el, Ελλάδα, Elláda, ), officially the Hellenic Republic, is a country located in Southeast Europe, Southeastern Europe. Its population is approximately 10.7 million as of 2021; Athens is its largest and capital city, followed ...

Greece
,
Italy Italy ( it, Italia ), officially the Italian Republic ( it, Repubblica Italiana, links=no ), is a country consisting of Italian Peninsula, a peninsula delimited by the Alps and List of islands of Italy, several islands surrounding it, whose ...

Italy
,
Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country A country is a distinct territorial body or political entity A polity is an identifiable political entity—any group of people who ...

Portugal
and
Cyprus Cyprus ; tr, Kıbrıs (), officially called the Republic of Cyprus,, , lit: Republic of Cyprus is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or politi ...

Cyprus
. They are also found in parts of
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
, such as
Mexico Mexico, officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the south and west by the Pacific Ocean; to ...

Mexico
, the ABC Islands, and areas of the
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, and sections of
South America South America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continent ...

South America
such as the ''
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'', the
Gran Chaco The Gran Chaco or Dry Chaco is a sparsely populated, hot and semiarid lowland natural region of the Río de la Plata basin, divided among eastern Bolivia, western Paraguay, northern Argentina, and a portion of the Brazilian states of Mato Gross ...
, and the poleward side of the arid deserts, where they typically feature a
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...
precipitation pattern, with generally rainless summers and wetter winters.


Cold semi-arid climates

Cold semi-arid climates (type "BSk") tend to be located in elevated portions of
temperate zones In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and planets. The first person to use ...
, typically bordering a
humid continental climate A humid continental climate is a climatic Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months t ...
or a
Mediterranean climate A Mediterranean climate or dry summer climate is characterized by dry summers and mild, wet winters. The climate Climate is the long-term pattern of weather Weather is the state of the atmosphere, describing for example the degre ...
. They are typically found in continental interiors some distance from large bodies of water. Cold semi-arid climates usually feature warm to hot dry summers, though their summers are typically not quite as hot as those of hot semi-arid climates. Unlike hot semi-arid climates, areas with cold semi-arid climates tend to have cold winters. These areas usually see some snowfall during the winter, though snowfall is much lower than at locations at similar latitudes with more humid climates. Areas featuring cold semi-arid climates tend to have higher elevations than areas with hot semi-arid climates, and tend to feature major temperature swings between day and night, sometimes by as much as 20°C (36°F) or more. These large diurnal temperature variations are seldom seen in hot semi-arid climates. Cold semi-arid climates at higher latitudes tend to have dry winters and wetter summers, while cold semi-arid climates at lower latitudes tend to have precipitation patterns more akin to
subtropical climate The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones located to the north and south of the tropics, Torrid Zone. Geographically part of the Geographical zone#Temperate zones, ...
s, with dry summers, relatively wet winters, and even wetter springs and autumns. Cold semi-arid climates are most commonly found in Asia and North America. However, they can also be found in Northern Africa, South Africa, Europe, sections of South America and sections of interior southern Australia (e.g.
Kalgoorlie Kalgoorlie is a city in the Goldfields–Esperance The Goldfields–Esperance region is one of the nine regions of Western Australia. It is located in the south eastern corner of Western Australia, and comprises the local government are ...

Kalgoorlie
and
Mildura Mildura is a regional city in north-west Victoria (Australia), Victoria, Australia. Located on the Victorian side of the Murray River, Mildura had a population of 33,444 in 2016. When nearby Wentworth, New South Wales, Wentworth, Irymple, Victor ...
) and New Zealand (around
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).


Regions of varying classification

In climate classification, any one of three isotherms may be used to delineate hot from cold semi-arid climates — that of average annual temperature; or that of the coldest month, either or . The warm side of the isotherm of choice is classified as BSh, the cooler side as BSk. As a result of these differing definitions, some areas can have climates that are classified as either hot or cold semi-arid, depending on the isotherm used. One such location is
San Diego, California San Diego ( , ; ) is a city in the U.S. state of California on the coast of the Pacific Ocean and immediately adjacent to the Mexico–United States border, Mexican border. With a 2020 population of 1,386,932, San Diego is the List of United ...

San Diego, California
(at its main airport). The city has cool summers for its latitude, due to prevailing winds off the ocean, so the average annual temperature is below ); however, winters are mild, with an average January temperature of , much closer to the coldest-month isotherm that separates tropical and subtropical climates than to the coldest-month isotherm that separates temperate and continental climates.


Charts of selected cities


See also

*
Continental climate Continental climates often have a significant annual variation in temperature (hot summers and cold winters). They tend to occur in the middle latitudes (40 to 55 north), within large landmasses where prevailing winds In meteorology Mete ...
*
Dust Bowl The Dust Bowl was a period of severe dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid A region is arid when it is characterized by a severe lack of available water, to the extent o ...
(an era of devastating dust storms, mostly in the 1930s, in semi-arid areas on the Great Plains of the United States and Prairies of Canada) *
Goyder's Line . George Goyder George Woodroffe Goyder in 1869 George Woodroffe Goyder (24 June 1826 – 2 November 1898) was a surveyor Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-di ...
(a boundary marking the limit of semi-arid climates in the Australian state of South Australia) *
Köppen climate classification The Köppen climate classification is one of the most widely used systems. It was first published by German-Russian (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist (1894- ...
*
Palliser's Triangle 300px, Map of Palliser's Triangle. Palliser's Triangle, or the Palliser Triangle, is a semi-arid A semi-arid climate, semi-desert climate, or steppe climate is the climate Climate is the long-term average of weather, typically averaged over a pe ...
(semi-arid area of Canada) * Ustic (Soil Moisture Regime) *
Wave height In fluid dynamics, the wave height of a ocean surface wave, surface wave is the difference between the elevations of a crest (physics), crest and a neighbouring trough (physics), trough. ''Wave height'' is a term used by sailor, mariners, as well ...


References


External links

{{Koppen Grasslands Köppen climate types Plains Prairies