The subtropics are geographic and climate zones located roughly between the tropic circle of latitude (the Tropic of Cancer and Tropic of Capricorn) and the 38th parallel in each hemisphere. Subtropical climate regimes can exist at high elevations within the tropics, such as across the Mexican Plateau and in Vietnam and Taiwan. Six climate classifications utilize the term to help define the various temperature and precipitation regimes for the planet Earth. Eight months of the year within the subtropics have an average temperature at or above , with their coldest month averaging between . A great portion of the world’s deserts are located within the subtropics, due to the development of the subtropical ridge. Within savanna regimes in the subtropics, a wet season is seen annually during the summer, which is when most of the yearly rainfall falls. Within Mediterranean climate regimes, the wet season occurs during the winter. Areas bordering warm oceans are prone to locally heavy rainfall from tropical cyclones, which can contribute a significant percentage of the annual rainfall. Plants such as date palms, citrus, mango, litchi (lychee), and avocado are grown within the subtropics. Tree ferns and sequoia also grow within subtropical climate regimes.