The tropical wet and dry climate, also known as the tropical savanna, is part of the Köppen climate classification system, which groups climates based on vegetation. Similar to the monsoon climate, the tropical climate is characterized by a wet season and a dry season. It is located between 5 degrees and 25 degrees latitude, in Central and South America, Africa, Australia and in southern Asia.
The tropical climate is found between the tropical wet climates, and the tropical dry climates in both the northern and the southern hemispheres. It ranges in latitude from between 5 degrees and 10 degrees to between 15 degrees and 20 degrees. Most people recognize the tropical savanna to be in Africa, though this climate is also found in Venezuela, Brazil, Central America, the Caribbean, Indo-China, areas of India and even parts of Florida.
Types of Season: Dry Season
The dry season in a tropical savanna lasts for most of the year when there is little or no rainfall due to continental tropical air masses and the sun is lower in the sky. In general, the higher the latitude of the region, the longer the dry season tends to be.
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Most dry seasons in the northern hemisphere begin around November and last through June when the rains return. In the southern hemisphere, dry seasons tend to last from about May through November. Temperatures reach their highest near the end of the dry season before the rains come. The average daily temperature in the dry season is in the upper 70s Fahrenheit, but, depending on the location, daytime temperatures can climb above 100 degrees Fahrenheit.
Types of Season: Wet Season
The wet season in the tropical savanna generally lasts from June to October in the northern hemisphere and from about December to April in the southern hemisphere. The rain results from a combination of warm, tropical air masses from large bodies of water and the sun positioned higher in the sky. Temperatures remain high during the wet season but can drop into the 50s at night. Depending on the location and the year, the wet season can result in annual rainfall of less than 10 inches to more than 50 inches.
Organisms in this climate depend on the cycle of wet and dry in order to survive. Without the wet season, the vegetation in the area wouldn't be able to survive through the dry season. But without the dry season, it would be too wet to form the environments that have formed there and would likely result in strictly forest environments as opposed to a variety of environments like savannas and grasslands.
Plants in Tropical Dry and Tropical Wet Climate
Because of the inconsistent rainfall, vegetation on the tropical savanna is not lush like it is in the rainforest or monsoon climate. Instead, tall grasses dominate the land, with sporadic areas of drought-resistant trees and shrubs. Plant life can have waxy leaves and thorns, which help it survive the dry climate. Some areas of woodlands and forests are found in this climate.
While farming does take place in the region, most involves the raising of livestock that can graze on the grass of the land. The rainfall pattern is not ideal for crop growth, though farms do produce a variety of products, including subtropical fruit, pearl millet, cowpeas, groundnuts, sorghum and various grains.
Larger animals found in the tropical climate are often migratory and travel in herds, such as the wildebeest, zebras and gazelles in Africa. These larger herbivores that survive on the grass of the savanna bring with them predators, such as lions in Africa and tigers in India. Smaller animals, such as rodents and small mammals, birds of prey and many species of insects, are also found in this climate.