While the tropical savanna biome does have two clearly delineated seasons, commonly referred to as a "winter" season and a "summer" season, these seasons are not accompanied by the extreme rise and fall in temperature associated with these seasonal distinctions. In fact, all tropical savannas are located in warm or hot climate zones, predominately latitudes 5 to 10 and 15 to 20. Annual temperatures range from about 64 degrees to 86 degrees. Temperature increases tend to be very gradual.
Winter is the dry season in the tropical savanna biome. This season typically ranges from November to April, and during this season the savannas typically receive an average of just four inches of rain. During much of this time, usually December through February, the savanna may be completely rain-free. This tends to be the cooler time of the year, with temperatures hovering around 70 degrees Fahrenheit. The dry season is typically heralded by violent October thunderstorms, and subsequent heavy winds which blow away the humidity and bring dry air. During January, at the peak of the dry season, the savanna often experiences widespread fires.
The hot humidity of the savanna's wet season earn the biome its "tropical" classification. Heavy rains begin in May or June; during May through October the savannas experience the majority of their 10 to 30 inches of annual rainfall. Humid air rising from the land clashes with the cooler atmosphere and becomes rain; during summer afternoons, savannas may experience hours of rainfall. The plants and animals of the savanna have adapted to living in semi-aquatic conditions during this time, and the savanna's porous soil helps it drain the rapid rains quickly.
During the summer rainy season, the savanna's grasslands grow thick and lush. Many of the biome's inhabitants give birth during this time, and the mothers' milk is dependent on rich grasses. During the dry season, many animals migrate. Others continue to feed off the savanna's grasslands, and are in turn eaten by carnivorous animals. Savanna plants are specially adapted to survive during the drought season, with deep roots, fire-resistant bark and storage systems for holding on to water during extended dry periods.
