Humid subtropical climate

Cfa: C = Mild temperate f = Fully humid a = Hot Summer

Cwa: C = Mild temperate w = Dry Winter a = Hot Summer [5][6]

In Africa, humid subtropical climates are primarily found in the southern hemisphere of the continent. The Cwa climate is found over a large portion of the interior of the Middle and Eastern African regions. This area includes central Angola, northeastern Zimbabwe, the Niassa, Manica and Tete provinces of Mozambique, the southern Congo provinces, southwest Tanzania, and the majority of Malawi, and Zambia. 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 Africa's 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.

In North America, humid subtropical climates are found in the American Gulf and lower East Coast states, including Texas, Oklahoma, Louisiana, Arkansas, Alabama, Mississippi, Tennessee, Kentucky, North Carolina, South Carolina, Georgia, and Florida. On the Florida peninsula, the humid subtropical climate gives way to the tropical climate of South Florida and the Florida Keys.

Under Köppen's climate classification, the climate can also be found in the Mid-Atlantic, primarily eastern Virginia, the lower elevations of West Virginia, Maryland, Delaware, Washington, D.C., New Jersey, southeastern Pennsylvania and far southern New York, specifically New York City and sections of Long Island. It can also be found in the Midwest, primarily in the central and southern portions of Kansas and Missouri, and the southern portions of Illinois, Indiana and Ohio.

In Mexico, there are small areas of Cfa and Cwa climates. The climate can be found in 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's climate is a major example of this.

Outside of isolated sections of Mexico, the southernmost limits of this climate zone in North America lie just north of South Florida and around southern coastal Texas. Cities at the southernmost limits, such as Tampa and Orlando and along the Texas coast around Corpus Christi down toward Brownsville generally feature warm weather year-round and minimal temperature differences between seasons. In contrast, cities at the northernmost limits of the climate zone such as New York, Philadelphia and Louisville feature hot, humid summers and chilly winters. These areas have average winter temperatures at the coldest limit of climates classed as humid subtropical.

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, Tampa, Houston, New Orleans, and Savannah rarely see snowfall, which occurs, at most, a few times per generation. In Southern cities farther north or inland, such as Atlanta, Birmingham, Charlotte, Dallas, Memphis, Nashville, Oklahoma City, and Raleigh, snow only occasionally falls and is usually three inches or less. However, for the majority of the winter here, temperatures remain above or well above freezing.[11][12][13] At the northernmost limits of this zone, cities such as New York City, Philadelphia, and Baltimore typically see snowfall during the winter, with occasional heavy snowstorms. Still, average temperatures during a typical winter hover just above freezing at these locations.[12][14][15][16] Precipitation is plentiful in the humid subtropical climate zone in North America – but with significant variations in terms of wettest/driest months and seasons. Much of the interior South, including Tennessee, Kentucky, and the northern halves of Mississippi and Alabama, tends to have a winter or spring (not summer) precipitation maximum. Closer to the South Atlantic and Gulf coasts, there is a summer maximum, with July or August usually the wettest month – as at Norfolk, Cape Hatteras and Jacksonville, North Carolina, Charleston, South Carolina, Mobile, Alabama and New Orleans. A semblance of a monsoon pattern (dry winters/wet summers) is evident along the Atlantic coast from southern North Carolina (Wilmington, North Carolina area) south to Florida. The seasonal monsoon is much stronger on the Florida peninsula, as most locations in Florida have dry winters and wet summers.

In addition, areas in Texas that are slightly inland from the Gulf of Mexico, such as Austin and San Antonio that border the semi-arid climate zone, generally see a peak of precipitation in May, a drought-like nadir in mid-summer and a secondary, if not equal, precipitation peak in September or October. Areas further south along South Texas' Gulf Coast (Brownsville), which closely border tropical climate classification, typically have a strong September precipitation maximum, and a tendency toward dry conditions in winter with rain increasing in spring, with December or January often the driest months.

Humid subtropical climates are found in a sizable portion of South America. The climate extends over a few states of southern Brazil, including Paraná, 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 and humid summers, and mild to cool winters. These areas, which include the Pampas, generally feature a Cfa climate categorization. At 38°S, the Argentine city of Bahía Blanca lies on the southern limit of the humid subtropical zone.

The Cwa climate occurs in parts of tropical highlands of São Paulo state, Mato Grosso do Sul 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 zone predominantly lies in eastern Australia, which begins from the coastal strip of Mackay, Queensland and stretches down to the southern coast of Sydney, where it transitions into the cooler, oceanic climates.[18][19]

From Newcastle, approximately 200 kilometres (124 mi) northeast of Sydney, the Cfa zone would extend to inland New South Wales, excluding the highland regions (which have an oceanic climate), stretching towards Dubbo to the northwest and Wagga Wagga to the south, ending at the New South Wales/Victoria border (Albury–Wodonga).[20] To note, these places would have characteristics of the semi-arid and/or Mediterranean climates. Furthermore, the inland Cfa climates generally have drier summers, or at least summers with low humidity.[21]

Extreme heat is more often experienced in Sydney than in other large cities in Australia's Cfa zone, especially in the western suburbs, where highs over 40 °C (104 °F) are not uncommon. Frost is prevalent in the more inland areas of Sydney, such as Richmond. Average annual rainfall in the Sydney region ranges between 800 and 1,200 millimetres (31.5 and 47.2 in).[22]

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 month (September). Temperatures are very warm to hot but are 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 which extends north to the Köppen Cwa classified climate zone of the Atherton Tablelands region. This region has a very pronounced dry winter period, with often negligible rainfall between June and October. Winter temperatures generally only fall slightly below 18 °C (64 °F), which would classify the region as a tropical savanna, or Aw, climate.

Annual rainfall within Australia's humid subtropical climate zone can reach as high as 2,000 millimetres (78.7 in) in coastal locations and is generally 1,000 millimetres (39.4 in) or above. The most intense 2-3 day rainfall periods that occur in this coastal zone however are the outcome of east coast lows forming to the north of a large high pressure system, there can be great variation in rainfall amounts from year to year as a result of these systems. As an example Lismore which lies in the centre of this zone, the annual rainfall can range from less than 550 millimetres (21.7 in) in 1915 to more than 2,780 millimetres (109.4 in) in 1950.[23]

The Po Valley, in Northern Italy, including major cities such as Milan, Turin, Bologna, and Verona, has a humid subtropical climate, featuring hot, humid summers with frequent thunderstorms; winters are foggy, damp and chilly, with sudden bursts of frost. Some parts of the valley have a mild continental climate. Places along the shores of Lake Maggiore, Lake Lugano, Lake Como (Como and Verbania in Italy and Lugano in Switzerland) have a humid subtropical climate with a distinctive high amount of rainfall during summer. Budapest, Hungary is just warm enough to qualify, due to recent warming. At 47°N, the city lies on the northern limit of the humid subtropical zone.

The coastal areas in the northern half of the Adriatic Sea also fall within this climate zone. The cities include Trieste, Venice, and Rimini in Italy, Rijeka and Split in Croatia, Koper in Slovenia and Kotor in Montenegro. Other Southern European areas in the Cfa zone include the central valleys and coast of Catalonia of Girona and Barcelona in Spain, some on the north-east of Spain (Huesca), West Macedonia in Greece (Kozani), the Garonne Valley (Toulouse) and Rhone Valley (Valence) in France.

Along the Black Sea coast of Bulgaria (Varna), coast of Romania (Constanta and Mamaia), Sochi, Russia and Crimea, have summers too warm (>22 °C (72 °F) in the warmest month) to qualify as oceanic, no freezing month, and enough summer precipitation and sometimes humid conditions, where they would be fit to be classed under Cfa, though they closely border the humid continental zone. All these areas are subject to occasional, in some cases repeated snowfalls and freezes during winter.

In Central Europe, a small area of humid subtropical climates are located in transitional areas between the oceanic and continental climates in areas where higher summer temperature do not quite qualify it for inclusion in the Oceanic climate schema (but, in the Trewartha climate classification, this type of climate is included in that typical of the other areas of central-west Europe, classified as Do -the Temperate Oceanic climate-) and mild winters do not allow their inclusion into continental climates. Average summer temperatures in areas of Europe with this climate are generally not as hot as most other subtropical zones around the world.

In the Azores, some islands have this climate, with very mild and rainy winters (>13 °C (55 °F)) and no snowfall, warm summers (>21 °C (70 °F)) but with no dry season during the warmest period, which means that they can neither be classified as oceanic, nor as Mediterranean, only as humid subtropical, 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 summer precipitation and poleward flow of tropical air-masses in summer are not present in Europe as they are in eastern Australia or the southern United States.

• Subtropics
• Subtropical ridge