Subtropics

The subtropical zones or subtropics are geographical and climate zones immediately to the north and south of the tropics. They are part of the temperate zones and cover the middle latitudes from about 23° to 35° to 40° north and south. This area includes the horse latitudes, a region where winds are often calm.

Subtropical climates usually have hot summers and mild winters. There are two main types: humid subtropical climates, where rain falls mostly in the summer, like in Southeast China and the Southeastern United States, and dry summer or Mediterranean climates, where rain falls mostly in the cooler months, like in the Mediterranean Basin or Southern California.

These climates can also be found at high elevations inside the tropics, such as in the southern part of the Mexican Plateau and Da Lat in Vietnam. Many of the world's deserts are located in the subtropics because of steady high-pressure systems. Areas near warm oceans often have wet, rainy summers, while areas near cool oceans tend to be dry and foggy. Common plants in subtropical regions include palms, citrus, mango, pistachio, lychee, and avocado.

Definition

See also: List of locations with a subtropical climate

The tropics are found between the Tropic of Cancer and Tropic of Capricorn, at about 23.5° north and south. The subtropics lie just beyond the tropics, roughly between 23.5° and 35° north and south.

Different scientists use various ways to describe the subtropical climate. One common method is the Trewartha climate classification, which says a subtropical area has at least eight months where temperatures average above 10°C (50°F) but at least one month where temperatures stay below 18°C (64.4°F). Other classifications also exist, each with its own rules for what counts as subtropical.

Rainfall

See also: Earth rainfall climatology, Subtropical ridge, Tropical cyclone, Subtropical cyclone, and Wet season

The sun heats the Earth most near the equator, causing warm air to rise and move towards the poles. As this air moves, it cools and sinks around the 30th parallel in both hemispheres, creating high-pressure areas known as subtropical ridges. These high-pressure areas often lead to dry conditions and many of the world's deserts, such as in Southern Africa and along the west coast of South America.

Some subtropical areas, however, get plenty of rain. In places like Australia, the Indo-Gangetic Plain, and parts of South America, summers are wet with frequent rainstorms, while winters are drier. Coastal regions influenced by warm oceans, such as the southeastern United States and Japan, can also receive heavy rain from tropical cyclones. The Mediterranean climate, found around the Mediterranean Sea, southwestern Australia, and near Santiago on the west coast of South America, has wet winters and dry summers.

Flora

The subtropics have warm winters that rarely freeze or snow, which helps plants like palms and citrus trees grow well. Farmers can also grow tropical crops such as mango, lychee, avocado, and aloe vera in these areas. The cooler winters make it easier to protect these crops from pests.

In subtropical areas, you can also find tree ferns (pteridophytes), along with plants like dracaena and yucca. Trees such as apple, pear, and pomegranate also thrive in the subtropics.

Varieties

Main article: Humid subtropical climate

Main article: Mediterranean climate

Main articles: Desert climate and Semi-arid climate

The subtropics have many different climate types. A humid subtropical climate has hot, sticky summers and mild winters. You can find this kind of weather in places like the southeastern United States, parts of China, and northern South Asia.

Another type is the Mediterranean climate, which has warm, dry summers and cooler, rainy winters. This climate is found around the Mediterranean Basin and also in parts of California, South Australia, and central Chile. Some subtropical areas are dry, with very little rain, known as desert or semi-desert climates.