Subtropics

The subtropics are geographic and climate zones located roughly between the tropics at latitude 23.5° (the Tropic of Cancer and Tropic of Capricorn) and temperate zones (normally referring to latitudes 35–66.5°) north and south of the Equator. Subtropical climates are often characterized by hot summers and mild winters with infrequent frost. Most subtropical climates fall into two basic types: humid subtropical, where rainfall is often concentrated in the warmest months (e.g. South China and the northeastern Southern Cone), and dry summer or Mediterranean climate, where seasonal rainfall is concentrated in the cooler months (e.g. the Mediterranean Basin and the west coast of the continental United States). Subtropical climates can occur at high elevations within the tropics, such as in the southern end of the Mexican Plateau and in the Vietnamese Highlands. Six climate classifications use the term to help define the various temperature and precipitation regimes for the planet Earth. A great portion of the world's deserts are located within the subtropics, due to the development of the subtropical ridge. Areas bordering warm oceans (typically on the southeast sides of continents) are prone to locally heavy rainfall from tropical cyclones, which can contribute a significant percentage of the annual rainfall. Areas bordering cool oceans (typically on the southwest sides of continents) are prone to fog, aridity, and dry summers. Plants such as palms, citrus, mango, pistachio, lychee, and avocado are grown in the subtropics. The tropics have been historically defined as lying between the Tropic of Cancer and Tropic of Capricorn, located at latitudes 23.45° north and south, respectively. According to the American Meteorological Society, the poleward fringe of the subtropics is located at latitudes approximately 35° north and south, respectively. Several methods have been used to define the subtropical climate. In the Trewartha climate classification, a subtropical region should have at least eight months with a mean temperature greater than 10 °C (50.0 °F) and at least one month with a mean temperature under 18 °C (64.4 °F). In most regions in this climate zone the coldest month has a mean temperature of above 7 C (45 F). In the Trewartha climate classification, most of these climates are located in the southernmost portions of the temperate zone (latitudes between 25 and 35 north and south). German climatologists Carl Troll and Karlheinz Paffen defined Warm temperate zones as plain and hilly lands having an average temperature of the coldest month between 2 °C (35.6 °F) and 13 °C (55.4 °F) in the Northern Hemisphere and between 6 °C (42.8 °F) and 13 °C (55.4 °F) in the Southern Hemisphere, excluding oceanic and continental climates. According to the Troll-Paffen climate classification, there generally exists one large subtropical zone named the warm-temperate subtropical zone, which is subdivided into seven smaller areas. According to the E. Neef climate classification, the subtropical zone is divided into two parts: Rainy winters of the west sides and Eastern subtropical climate. According to the Wilhelm Lauer & Peter Frankenberg climate classification, the subtropical zone is divided into three parts: high-continental, continental, and maritime. According to the Siegmund/Frankenberg climate classification, subtropical is one of six climate zones in the world.