Tanzania is located a few degrees south of the equator and has a tropical climate, influenced mainly by its altitude. The main rainy season (called masika in Kiswahili) is in April and May, and typically there is heavy rain (especially in the afternoon) which is more regular on the coast than it is inland. June to October is certainly the driest time, with cooler temperatures than the rest of the year. The south wind, known as the kusi, keeps the islands and the coast breezy. The long dry season is followed by the short rains or mvuli, usually from mid-November to early December, during which the rains are scanter and more sporadic than during the masika. The shorter rainy season is followed by another dry season, lasting from late December to late March. During this time temperatures are higher than they are from June to October and there are occasional showers.
In general, the Northern Highlands enjoy lower temperatures and less humidity than the coastal lowlands and the islands.
Considering that climate change now affects the whole planet and that the weather has become increasingly unpredictable at all latitudes, let’s see if we can work out the best times to visit the various parts of the country.
The best times to visit the north of Tanzania are from December to March and from June to October. Mid-January to early April is perhaps the best time to visit the Serengeti, because it is when the great migrant herds of wildebeest and zebras gather in the south-central sector. The wettest time is usually mid-April to mid-May. Occasional downpours between mid-November and mid-December will not disturb your itinerary in the north: if anything they wash the dust from the tracks and contribute to lowering the temperature by a few degrees.
The best time to visit the south of the country is from June to December. From June to October temperatures are usually lower and from March to April is by far the wettest time.
Along the coast and on the islands the best times are from December to March, when daytime temperatures exceed 30°C and the sea is incredibly warm, and from July to October, which are cooler and breezy.