Between December and February no rain will fall at all. Oddly enough, it is actually a little cooler during this dry season. But don't expect sweater weather; it is still around 70° F.
In the summer there is lots of rain. In Africa the monsoon rains begin in May. An average of 15 to 25 inches of rain falls during this time. It gets hot and very humid during the rainy season. Every day the hot, humid air rises off the ground and collides with cooler air above and turns into rain.
In the afternoons on the summer savanna the rains pour down for hours. African savannas have large herds of grazing and browsing hoofed animals. Each animal has a specialized eating habit that reduces competition for food.