Just south of the equator, Tanzania is huge and its sheer size means that the climate varies considerably within it. However, generally the main rainy season, or the ‘long rains’, lasts during about March, April and May. Afternoon tropical downpours are the norm – which are heavier and more predictable beside the coast and on the islands. 
The humidity is high and daily temperatures reach the low-mid 30°s.
The long dry season lasts throughout June, July, August, September and October is when rainfall is unusual, even on the islands. Temperatures vary hugely with altitude and location, but it’s usually a fine, clear sky and sunny weather – it’s a great time to visit Tanzania. During November and December there’s another rainy season: the ‘short rains’. These are much lighter than the main rains and less reliable.
The best time to visit Tanzania
The best wildlife viewing months in Tanzania are during the Dry season from late June to October. The best chance of seeing the wildebeest migration in the Serengeti is during June and July and the time to see the wildebeest calving is late January to February. The southern and western circuit parks are best visited during the Dry season (June to October), unlike the more popular northern circuit parks that can be visited year-round. Tarangire is the only exception since its wildlife viewing is considerably better in the Dry season as well.
