Climate
Seasons
One of the largest defining factors in the tropical savanna is the presence of two distinct seasons: the dry/cooler season and the wet/warmer season. The wet and dry seasons change depending on the region that the savanna is in. For example, the climate in Kano, Nigeria has it's wet season between May and September, while the climate in Nairobi, Kenya experiences it's wet season in November through March. These seasons are caused by the rising of hot, humid air clashing with cool air, causing rain, and the reversal of such an effect. During the dry season, the sun is typically at a lower angle, at least in some savannas. There are obvious physical differences between the wet and dry seasons, as demonstrated above. In the dry season (to the left), the savanna is wet and dusty, while in the wet season, the vegetation is green and rainclouds are on the horizon.
Precipitation and Temperature
As due to the two seasons mentioned above, the temperature and precipitation rates are varied throughout the year. In the wet season, temperatures are usually around 78-86 degrees Fahrenheit (25-30 degrees Celsius), and the rainfall is between 15 and 25 inches. In the dry season, it may only rain as little as four inches, and the temperatures lower to 68-78 degrees Fahrenheit (20-25 degrees Celsius). The average temperature is in the mid-70s (Fahrenheit), and the average rainfall can be between 10 and 30 inches.
Climate Zone
As the name may imply, tropical savannas are found in the tropical climate zone, between approximately 30 degrees north of the equator and 30 degrees south of it (the Tropics of Cancer and Capricorn).