Zanzibar and the Swahili coast, a humid and hot climate
On the Zanzibar archipelago. Zanzibar has mild to hot temperatures, but a pleasantly humid tropical climate. Zanzibar is a year-round destination, except from March to May, during the rainy season. The high season in August and at Christmas is crowded, while June, September, December, January and February are particularly recommended. The short rainy season in October and November is very pleasant, and it never gets cold. If it rains lightly, it's still warm, humid and sunny; no problem to enjoy the beach between short showers. For diving and deep-sea fishing, the best season is August and September, and March and April. In Mafia, the whale shark-watching season runs from September to February, so book in advance. The wind is strongest in winter, ideal for kitesurfing in Zanzibar in July and August.
On the Swahili coast, from Tanga (on the Kenyan border) to Mtwara (on the Mozambican border), via Kilwa and Mafia Island, the climate is a little different from that of Zanzibar. It's warm all year round, with a high level of humidity, ideal for seaside holidays. It rains from March to early June, the main rainy season, and intermittently from October to February. It gets really hot (often over 35°C, with high humidity), especially from December to March.
Kilimanjaro, an extreme climate and a defined seasonality
On Tanzania's two great volcanoes, the main rainy season is slightly staggered. In January and February, nightly snowfalls cool the atmosphere of the peaks, but make them look superb. It gets very, very cold in July and August, especially on the eastern and southern slopes. At the summit, it can be between -5 and -20°C! You'll need to be well equipped. The best seasons for clear skies all the way to the summit are January and February, the warmest months in the short dry season, and especially July, August and September during the long dry season. But it's very cold there. June and September are interesting alternatives, as they are less frequented. During the rainy season, from March to May, the hottest months, visibility is reduced by heavy clouds, particularly at the summit, which can cause dangerous snowfalls and downpours. This season should be avoided.
In the north and centre, an African highland climate
In the north. The Serengeti highlands lie at an altitude of around 1,500 metres. Tarangire Park (home to many elephants) lies 1,100 m above sea level, Lake Manyara fluctuates between 900 and 1,500 m, while the crater of the Ngorongoro volcano dominates the Serengeti plain at 2,200 m. Average temperatures fluctuate between 15 and 25°C in the Tanzanian highlands, but it gets downright cold at night on the rim of the Ngorongoro crater, especially from June to September, when the thermometer drops very low at night. If you have to sleep in a tent, pack warm. The main rainy season sees between 130 and 140 mm of rainfall per month, from March to mid-May. The short rainy season (fairly unpredictable) takes place in November and December (around 110 mm of rain per month). We advise you to avoid the long rainy season.
The long dry season. This is the ideal season for a safari in the northern highlands, in Maasai country, from mid-May to the end of October. Specifically in the national parks of Serengeti, Tarangire, Lake Manyara, Ngorongoro Crater, the Lake Natron region and Mwanza on Lake Victoria. However, we advise you to avoid the Christmas vacations, and the period from mid-July to the end of August in the most touristic parks: lots of vehicles in the Ngorongoro Crater or on the Seronera plain (in the heart of the Serengeti). The ideal time to visit is in September or October, at the end of the dry season, as the less water there is, the better the visibility in the bush, as the grass is shorter, the paths more practicable, the temperatures pleasant, and the animals very mobile in search of watering holes at dawn and dusk.
The short shoulder season. This is a possible period for a safari in the region, in January and February, even if rainfall is still fairly abundant (we can't talk about a short dry season). In this region, wildlife is so abundant that you're guaranteed to see groups of lions, cheetahs, leopards and elephants in the Serengeti, Tarangire and Ngorongoro Crater parks. Even so, rainfall is around 90 mm per month.
Wildebeest migration. If you want to witness the wildebeest migration in the Serengeti, this is a special case as it takes place from November to June, with the wildebeest preceding the rain and migrating clockwise (to and from Kenya).
In the center. In the central region of Dodoma, Iringa and Ruaha National Park, temperatures fluctuate between 15 and 27°C, as the central highlands still moderate temperatures, but the climate is very dry. Dodoma lies at an altitude of 1,100 m, while Iringa is perched at 1,500 m. The dry season lasts from early May to late October, but rainfall is still low in November. From July to September, Ruaha Park is shaped by sandy rivers where elephants frolic. In October and November, jacaranda trees add color to the landscape.
In the south and west, an arid bush climate
The south, particularly Morogoro, Mikumi National Park, Selous and Lake Malawi reserves (on the border with Malawi and Zambia) are subject to a similar but hotter and more arid climate. A bush climate experienced only by the most adventurous of travellers, and tourists in small charters landing directly in the heart of the parks and safari reserves. Similarly, in the west of the country, the Tanganyika Lakes region is low in altitude and stiflingly hot. Only the town of Kigoma lies at an altitude of 780 m.
