Tanzania has very different climatic conditions due to the different landscape forms and altitudes
The coastal zone is hot with high humidity (at 8 o'clock 83 percent, at 14 o'clock 71 percent annual average). The average daytime temperatures are about 26.5 to 30°C. The climatically most favourable months are June to September, the humidity is low and the sky almost cloudless. Cool winds blow from the sea. The rainy season runs from March to May. The hottest time of the year is between October and February. The average annual temperature in Dar es Salaam is about 26°C.
The central plateau, which is about 1,200 m high, has strongly fluctuating day temperatures. During the day it is hot here and at night it is very cool.
The lake areas have a higher humidity than the central plateau and also stronger rainfalls.
The zone between coastal plain and central plateau, in the Usambara mountains, northwest of Tanga and in the Kilimanjaro area has a temperate climate. During the small rainy season from October to November it is hot with high humidity, but during the rest of the year it is pleasant as the air is usually cool (about 22°C). The northern coastal area and the north-east and north of the country have a double rainy season. From March to May the great rainy season, followed by the dry season, and in the months of October/November the small rainy season, followed by the small dry season from December to February, which sometimes brings only a weakening of precipitation.
Towards the interior of the country, as well as to the south and southwest, this double rainy season shrinks into a single one, which lasts from November/December to April.
Zanzibar and Pemba record heavy rainfall from April to May, while in November and December it weakens. Temperatures range from 17-24°C to about 32°C. The coolest and driest period is between June and October, when the wind blows constantly from the southwest.
June to September are the most pleasant months for trips to Tanzania, but can be cool in the mountains. In the north, January to mid-March is ideal.