File Koppen World Map Cwa Cfa.png
A humid subtropical climate
(Köppen climate classification Cfa
is a zone of subtropical climate
characterized by hot, humid summers and generally mild to cool winters. Under the Köppen climate definition, this category of climate type covers a broad range of attributes, especially in terms of winter temperatures. The term "subtropical" may be a misnomer for locations along the cooler ranges.
The Köppen definition of this climate is for the coldest months mean temperature to be between and and the warmest month to be above
Some climatologists prefer to use as the lower bound for the coldest months mean temperature. It is either accompanied with a dry winter (Köppen: w
[Köppen: w — driest winter month receives less than one tenth of the precipitation of the wettest summer month]
) — or has no distinguished dry season (Köppen: f
[Koppen: f — winter months get more than one tenth of the precipitation of the wettest summer month, and summer months get at least per month or more than one third as much the wettest winter month]
[The Times Atlas of the World(1993). Times Books ISBN 0-7230-0492-7.]
Significant amounts of precipitation occur in all seasons in most areas, and though in regions bordering on semi-arid climate
(usually at the western margins), irregular droughts
can be common and catastrophic to agriculture
Winter rainfall (and sometimes snowfall
is associated with large storm
that the westerlies
steer from west to east. Most summer rainfall occurs during Air-mass thunderstorm
and an occasional tropical storm Tropical cyclone
Overview of distribution
Humid subtropical climates normally lies on the southeast side of all continent
, generally between latitude
25° and 40° north and tend to be located at coastal or near coastal locations. However in some cases the climate extends well inland, most notably in China and the United States.
In Africa, the humid subtropical climates are found in two separate areas on the southern hemisphere of the continent. The Cwa
climate is found over a large portion of the interior of the Central Africa
and East Africa
regions. This area includes; central Angola
the Niassa Province Manica Province
and Tete Province
provinces of Mozambique
the southern Democratic Republic of the Congo
provinces, southwest Tanzania
and the majority of Malawi
Some lower portions of the Ethiopian Highlands
also have this climate. The climate is also found in the narrow coastal sections of southern and eastern South Africa
primarily in KwaZulu-Natal
and the Eastern Cape
provinces. South Africas version of this climate features heavy oceanic influences resulting in generally milder temperatures. This is particularly evident in its winters when temperatures do not drop as low as in many other regions within the humid subtropical category.
Locations in Asia with a humid subtropical climate differ from those in other continents in that they often have marked seasonal differences in precipitation, if not very dry winters.
In East Asia
this type climate is found the southeastern quarter of mainland China
the northern half of Taiwan, northern Vietnam, narrow areas along the coast of South Korea, and Japan (Kyushu Shikoku
and most of Honshu
. Cities near the equatorward boundary of this zone include Hong Kong Hanoi
is near the northern boundary.
The influence of the strong Siberian anticyclone
in East Asia brings colder winter temperatures southward, pushing the 0 °C isotherm as far south as the valleys of the Yellow River
and Wei River
roughly 34th parallel north
At Hainan Island
and in Taiwan, the climate transitions from subtropical into fully tropical. In most of this region, there is extremely limited precipitation during the winter, owing to the Siberian anticyclone
from Siberia. Only in inland areas below the Yangtze River and coastal areas between approximately the Huai River
and the beginning of the coast of Guangdong
is there sufficient winter rainfall to produce a Cfa
climate; even in these areas, rainfall and runoff (water)
show a highly pronounced summer peak quite unlike other regions of this climate type. The only area where winter precipitation equals or even exceeds the summer rain is on the "San-in" (Sea of Japan
, or western, coast of Japan, which during winter is on the windward side of the westerlies. The winter precipitation in these regions is usually produced by low-pressure systems off the east coast that develop in the onshore flow from the Siberian high. Summer rainfall comes from the East Asian Monsoon and from frequent typhoon
. Annual rainfall is generally over and in areas below the Himalayas can be much higher still.
Humid subtropical climates can also be found in South Asia
primarily along the Ganges river. However, the humid subtropical climates exhibited here differ markedly from humid subtropical climates in East Asia
(and for that matter a good portion of the globe). Winters here are typically mild, dry and relatively short. They also tend to be foggy. Summers tend to be long and very hot, starting from mid-April and peaking in May and early June with high temperatures often exceeding 40°C. They also tend to be extremely dry, complete with dust storms
traits usually associated with arid climate
or semiarid climate
. During this period many native trees defoliate to save water. This is followed by the cooler monsoon
, where the region experiences heavy rains on almost a daily basis. Average high temperatures decreases during the monsoon season but the humidity increases. This results in hot and humid conditions, similar to summers in humid subtropical climates. Cities such as New Delhi Lucknow Kanpur
exhibit this atypical version of the climate in India. In Pakistan, the twin cities of Rawalpindi Islamabad
also feature this weather pattern, but with wetter and relatively cooler winters.
In South Asia, humid subtropical climates generally border on continental climates as altitude increases, or on winter-rainfall climates in Pakistan. Further east, in highland areas with lengthier monsoons such as Nepal, seasonal temperature variation is lower than in the lowlands.
Southwestern Asia (Northern Middle East and Caucasus)
Although humid subtropical climates in Asia are mostly confined to the southeastern quarter of the continent, there are areas on the Caspian Sea
and Black Sea
with humid subtropical climates that are unusually warm for their high latitudes and also unusual for this climate type, that snowfall in winter is relatively common, but is usually of a short duration.
In Southwestern Asia, the climate is prevalent in the Gilan of Iran
in parts of the Caucasus, in Azerbaijan
and in Georgia (country)
wedged between the Caspian Sea
and Black Sea
seas. The climate is also present in small areas of the southern Russian Federation
and coastal (Black Sea) Turkey. In the narrow Caspian Sea
coastal strip of Iran
and Māzandarān Province
a humid subtropical climate prevails . Annual rainfall ranges from around 740 mm (29 inches) at Sari, Iran
to over 2,000 mm (78 inches) at Bandar-e Anzali
and is heavy throughout the year, with a maximum in October or November when Bandar-e Anzali
can average 400 millimetres (16 inches). Temperatures are generally moderate in comparison with other parts of Southwestern Asia. In Rasht
the average maximum in July is around 28 °C (82 °F) but with near-saturation humidity
whilst in January it is around 9 °C (48 °F). The heavy, evenly distributed rainfall extends north into the Caspian coastal strip of Azerbaijan (country)
up to its northern border but this climate in Azerbaijan is, however, a CfbCfa
(Oceanic climateHumid subtropical climate
borderline case. During winter, the coastal areas can receive snowfall, but is usually of a short duration.
Annual rainfall in Lankaran
in the southeast averages up to 1,800 mm (70 inches) and is heavy throughout the year; and annual rainfall is generally over 1,000 mm (40 inches) in the foothills of the Caucasus in the northeast, as altitude increases and the humid subtropical climate changes to the oceanic climate
[Climate in Azerbaijan http://www.azhydromet.com/SRIH/Water%20Resurs.html].]
Western Georgia (country)
in the Colchis
and the north coast of Turkey
have a climate similar to that of Gilan and Mazandaran in Iran and very similar to that of southeastern and northern Azerbaijan. Temperatures range from 22 °C in summer to 5 °C in winter and rainfall is even heavier than in Caspian Iran, up to 2,300 millimetres per year in Hopa
(Turkey) and up to 2,718 millimetres per year in Batumi
(Georgia) falling throughout the year. This climate in northern Turkey and western Georgia is, again, a CfbCfa
(Oceanic climateHumid subtropical climate
borderline case. And again, during winter, the coastal areas can receive snowfall, but is usually of a short duration.
In North America, humid subtropical climates are almost exclusively the domain of the American South, including the following states: the eastern half of Texas Oklahoma Louisiana Arkansas Alabama Mississippi North Carolina South Carolina Tennessee Georgia (U.S. state) Kentucky
most of Florida
and sections of West Virginia
The climate in many of these states is subject to extremes. The humid subtropical climate can also be found in the Mid-Atlantic states
primarily Maryland Delaware Washington, D.C.
southern New Jersey
and far southern New York State
specifically New York City
and Long Island
It can also be found in the Midwest, primarily in the central and southern portions of Kansas
and the southern portions of Illinois Indiana
The Mid-Atlantic and Midwestern areas included in this climate typically see snowfall during the winter, with occasional heavy storms. On the other extreme end, most of Florida only occasionally see the extremes that are more commonplace in the rest of the American South. In southern Florida, the climate is tropical
The archetypal humid subtropical climate is best exemplified by the American Deep South
because the summers are long and almost tropical, and temperatures reach freezing only a few times in the winter with rare snowfall, usually three inches or less. Summers in this zone are hot and humid, with daily averages above with average daily maxima above .
there are small areas of Cfa
climates. The climate can be found small areas scattered around the northeastern part of the country, in proximity to the Gulf of Mexico
Other areas where the climate can be found is in the high elevations of Trans-Mexican Volcanic Belt
and Sierra Madre Oriental
Despite being located at higher elevations, these locations have summers that are too warm to qualify as a subtropical highland climate Guadalajara, Jalisco
s climate is a major example of this.
Characteristics and variants
Outside of isolated sections of Mexico, the southernmost limits of this climate in North America lie just north of South Florida
and around southern coastal Texas
Cities at the southernmost limits of this climate, such as Orlando, Florida
and Tampa, Florida
and along the Texas coast around Brownsville, Texas
generally feature warm weather year round and minimal temperature differences between seasons. These cities fall just short of having a true tropical climate
In contrast, cities at the northernmost limits of the humid subtropical region, such as New York City
[lt;/ref>] [lt;/ref> Philadelphia and Louisville, Kentucky feature winters that are barely warm enough to qualify as a humid subtropical climate. These cities generally experience much greater seasonal variation, featuring hot, humid summers and chillier winters. Areas farther north than this, inland, or at a higher elevation, fall into the humid continental climate category with harsher winters.
Snowfall varies greatly in this climate zone. In locations at the southern limits of this zone and areas around the Gulf Coast cities such as Orlando, Florida Tampa, Florida Houston, TX and New Orleans, Louisiana rarely see snowfall, which occurs, at most, a few times per generation. In Southern cities farther north or inland, such as Birmingham, Alabama Atlanta Memphis, Tennessee Little Rock, Arkansas Nashville, Tennessee Dallas Norfolk, Virginia Charlotte, North Carolina and Raleigh, North Carolina snow typically falls once or twice a season and is usually three inches or less. Ice storms are not unusual at these locations. However for the majority of the winter here, temperatures remain above or well above freezing, with slight plant growth. In the northern limits of this climate zone, cities such as Philadelphia and New York City experience snow every winter, sometimes accumulating heavily although it melts more quickly than in regions to the north.
Precipitation is plentiful in the humid subtropical climate zone in North America. Although most areas tend to have precipitation spread evenly throughout the year, a somewhat monsoon-like pattern is seen in parts of the Southeast (in locales such as Augusta, Georgia and Columbia, South Carolina , which experience dry winters (by humid subtropical standards) and warm springs, followed immediately by a long, hot, rainy and humid summer. In addition, areas in Texas that are slightly inland from the Gulf of Mexico such as Austin, Texas and San Antonio that border the semi-arid climate zone, generally see a peak of precipitation in the spring, and a deep, drought-like nadir in mid-summer.
Humid subtropical climates are found in a sizeable portion of South America. The climate extends over a few states of southern Brazil, including Paraná (state) into sections of Paraguay all of Uruguay and the Río de la Plata region in Argentina. Major cities such as São Paulo Buenos Aires Porto Alegre and Montevideo have a humid subtropical climate, generally in the form of hot humid summers and mild to cool winters. These areas, which include the Pampas generally feature a Cfaclimate categorization.
The Cwaclimate occurs in parts of tropical highlands of São Paulo (state) state, Minas Gerais and near the Andean highland in northwestern Argentina These highland areas feature summer temperatures that are warm enough to fall outside the subtropical highland climate category.
The humid subtropical climate dominates half of eastern Australia.
This zone contains the only regions where soil are not acutely deficient in phosphorus as well as the heaviest rainfall south of the Tropic of Capricorn, making it prime agricultural country, centred on towns such as Coffs Harbour, New South Wales Grafton, New South Wales Kempsey, New South Wales Port Macquarie, New South Wales Tamworth, New South Wales and Moree, New South Wales
Variations in Australia
There is variation in climate within this zone. Annual rainfall on the coast can reach as high as 2,000 mm (80 inches) in favourable locations and is generally above 1,000 mm (40 inches).However, because most of the heaviest two- and three-day rainfalls in the world occur in this coastal zone as a result of east coast lows forming to the north of a anticyclone there can be great variation in rainfall from year to year. At Lismore, New South Wales in the centre of this zone the annual rainfall can range from less than 550 mm (22 inches) in 1915 to more than 2,780 mm (110 inches) in 1950.
[http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode139&p_display_typedataFile&p_stn_num058037 058037 Lismore (Centre Street) monthly rainfall]] There is usually a distinct summer rainfall maximum that becomes more pronounced moving northwards: in Brisbane the wettest month (February) receives five times the rainfall of the driest (September). Temperatures are very warm to hot but not excessive: the average maximum in February is usually around 29 °C (84 °F) and in July around 21 °C (70 °F).Frosts are extremely rare except at higher elevations, but temperatures over 35˚C (95˚F) are not common on the coast.
North of the Cfa climate zone there is a zone centred upon Rockhampton, Queensland and extending up to the Atherton Tableland of Köppen Cwa climate.This has a very pronounced dry winter with often negligible rainfall between June and October, and winter temperatures generally only slightly below 18°C, above which one would have a tropical savanna, or Aw climate.
Humid subtropical climates are located in relatively small sections of Europe. The Toulouse region of France, and in places along the Adriatic and Black Sea coasts which are too wet for inclusion in the Mediterranean climate schema, inland from these areas there are isolated pockets where the climate is borderline subtropical but these zones are usually classed as oceanic or humid continental. Average summer temperatures in areas of Europe with this climate are generally not as hot as most other subtropical zones around the world, but the growing season can be adequately long.
Some areas of Europe, such as parts of the northeastern interior of the Iberian Peninsula particularly in Catalonia southern France Garonne and Rhone Adriatic northern Italy parts of Epirus in Greece around the area of Ioannina most of the Vardar Valley in the Republic of Macedonia parts of coastal northern Croatia coastal Slovenia and Central Serbia fall into this classification. Along the Black Sea coast of Bulgaria Romania Sochi, Russia and southernmost Ukraine have summers too warm (>22°C in the warmest month) to qualify as oceanic, no freezing month, and enough summer precipitation and sometimes humid conditions to preclude their classification as Mediterranean climate but rather border on or are sometimes defined as Humid continental climate . All these areas are subject to occasional, in some cases repeated snowfalls and freezes during winter. In the Azores some islands have this climate, with very mild and rainy winters (> 13°C) and no snowfall, hot summers (> 22 or 23°C) but with no dry season during the warmest period, which means that they can be classified neither as oceanic, nor as Mediterranean, but only as humid subtropical climate, as with Corvo Island
In many other climate classification systems outside of the Köppen, most of these locations would not be included in the humid subtropical grouping. The higher precipitation and high humidity of summers is not present nearly to the degree that it is in subtropical regions of North America and Asia, making its distinction in Europe all the more difficult.
*Köppen climate classification
Category Köppen climate classifications
Category Climate of Africa
Category Climate of Asia
Category Climate of Australia
Category Climate of Europe
Category Climate of North America
Category Climate of South America