Tanzania has a tropical climate whose character is set by altitude and by two different rainfall regimes. The Indian Ocean coast around Dar es Salaam is hot and humid all year, with average highs near 31 °C and about 1,120 mm of rain; the central plateau around Dodoma is semi-arid, with under 600 mm a year and almost no rain from June to October; the northern highlands around Arusha, at 1,400 m, are mild, with average highs near 25 °C; and the summit of Kilimanjaro (5,895 m), Africa's highest point, has an ice-cap climate averaging about −7 °C. The north and the coast get two rainy seasons, the long masika rains from March to May and the short vuli rains in November and December, while the south, centre and west get a single rainy season from about October or November to April. Across most of the country June to October is the main dry season, and the great wildebeest migration of the Serengeti moves with the rains.
Dar es Salaam and the Swahili Coast: Heat, Humidity and Two Rains
Tanzania's 1,424 km coastline faces the warm western Indian Ocean, and the coastal strip, together with Zanzibar, Pemba and Mafia islands, is the hottest and most humid part of the country. Dar es Salaam, the largest city with more than 7 million people, has a tropical savanna climate (Köppen Aw/As). At Julius Nyerere International Airport, the 1991–2020 averages give a yearly mean high of 31.2 °C and a mean low of 22.0 °C. February is the warmest month, with average highs of 32.8 °C, and the coolest nights come in July and August, when lows fall to about 19 °C. The station's record high is 36.9 °C, set in March, and its record low is 12.8 °C, set in August.
Annual rainfall at the airport averages 1,117 mm, spread over about 83 rain days. The monthly figures show the coast's two-season rhythm. Rain builds from March, peaks at 264 mm in April and stays high through May, then almost disappears: June to September each bring 16 to 31 mm. A second, smaller rise follows in November and December.
The coast also sits at the edge of the South-West Indian Ocean cyclone belt, although direct hits are rare. In May 2024 Tropical Cyclone Hidaya, after peaking with one-minute sustained winds of 80 knots, weakened to a tropical storm and made landfall at Kilindoni on Mafia Island. It was one of very few recorded landfalls in Tanzania, after a cyclone over Zanzibar in 1872, an unnamed storm in 1952 and Tropical Depression Atang in 2002. Hidaya killed at least five people, damaged or destroyed 1,555 houses and halted ferries between Zanzibar and Dar es Salaam, arriving after weeks of flooding from the long rains.
Dodoma and the Semi-Arid Central Plateau
Inland, the land climbs onto the central plateau, part of the East African Plateau, and the climate dries out sharply. Dodoma, the national capital since 1996 and 453 km west of Dar es Salaam, has a semi-arid climate. Its 1991–2020 averages give 594.5 mm of rain a year on about 42 rain days, roughly half the coastal total. Almost all of it falls between December and April; December (143 mm) and January (140 mm) are the wettest months, while June, July, August and September each average less than 1 mm.
Dodoma's temperatures are warm rather than hot, because of its elevation. The yearly mean high is 29.1 °C and the mean low 17.4 °C, with July nights dipping to about 13 °C. The pattern here is unimodal: one long wet season rather than two separate rains. From May to October the city records barely 11 mm of rain in total, against 143 mm in December alone: a short burst of heavy rain followed by about six months of near-total dryness.
Arusha, Mbeya and the Cool Highlands
The highlands of the north and south-west are where Tanzania feels least tropical. Arusha, at about 1,400 m on the southern slopes of Mount Meru, has a subtropical highland climate (Köppen Cwb). Temperatures typically range between 10 and 30 °C, with an average annual high of around 25 °C. The record high since records began there in 2000 is 39 °C and the record low 7 °C. Annual rainfall averages 1,180 mm, and Mount Meru shapes it: areas north and north-east of the city are wetter and cooler, while the mountain's rain shadow reaches its south-eastern side. Land just south and west of Arusha drops back into tropical savanna (Aw).
Mbeya, the main city of the Southern Highlands, north-west of Lake Malawi, is also classed as Cwb. Its general temperature range runs from −6 °C on highland mornings to 29 °C on lowland afternoons. June to October is dry and cold, and the heaviest rain falls from December to April, giving about 900 mm a year. Around Tukuyu, south of Mbeya, abundant and reliable rain on volcanic soils supports intensive farming. Across the highlands as a whole, temperatures generally range between about 10 °C in the cold season and 20 °C in the hot season.
Kilimanjaro's Five Climate Belts and Its Vanishing Ice
Mount Kilimanjaro packs most of Tanzania's climates, and one it has nowhere else, onto a single mountain. Climbers usually describe five zones: bushland and cultivated lower slopes from 800 to 1,800 m, rainforest from 1,800 to 2,800 m, heather and moorland from 2,800 to 4,000 m, alpine desert from 4,000 to 5,000 m, and an arctic summit zone from 5,000 m to the top at 5,895 m.
Rainfall follows the same staircase. The lower southern slope receives 800 to 900 mm a year, rising to 1,500 to 2,000 mm at 1,500 m and to more than 3,000 mm in places in the forest belt between 2,000 and 2,300 m. Above that it falls away, to about 200 mm in the alpine zone. The northern slopes are much drier than the southern ones. The mountain shares the region's two rainy seasons, March to May and around November, and upslope winds by day and downslope winds at night are stronger on the broader southern flank.
The summit has an ice-cap climate (Köppen EF). Its average temperature is about −7 °C. On the Northern Ice Field, night-time surface temperatures average −9 °C and daytime highs −4 °C, and on clear nights of strong radiational cooling the ice can fall to between −15 and −27 °C. Snow and graupel add 250 to 500 mm of precipitation a year, mostly during the rainy seasons.
The ice itself is disappearing. In the late 1880s an ice cap of about 20 km² covered Kibo's summit. Between October 1912 and June 2011 ice cover shrank from 11.40 km² to less than 1 km², a loss of almost 85 per cent, and of the ice still present in 2000 almost 40 per cent had gone by 2011. The yearly loss rate accelerated from about 1.1 per cent in 1912–1953 to 2.5 per cent in 1989–2007. Scientists attribute much of the slope glaciers' retreat to falling humidity rather than warming, since air at that height stays below freezing, and sunlight melts the exposed vertical ice walls. A 2013 estimate concluded that most of the ice would be gone by 2040 and that it was highly unlikely any would remain after 2060. The rest of the mountain's story is in our complete guide to Mount Kilimanjaro.
Masika, Vuli and the Unimodal South
Tanzanian weather makes sense once you see the split between bimodal and unimodal rainfall, both driven by the seasonal north–south migration of the Intertropical Convergence Zone. The two-season, bimodal zone runs from Lake Victoria east across the northern highlands to the coast, where the rain belt passes overhead twice a year. In Swahili, the long rains of March to May are the masika, the less reliable short rains of November and December are the vuli, and the dry season from June to October is the kiangazi. Farmers around Arusha plant many crops twice a year to use both rains.
Further south the two passages merge into one. Across the southern, central and western parts of the country, a single rainy season runs from about October to April. Mwanza, on the southern shore of Lake Victoria, sits close to the boundary: it has wet peaks in April (173 mm) and November (158 mm) and even its driest month, July, averages 5 mm. Nationally, the hottest period runs from November to February, with temperatures of about 25 to 31 °C, and the coolest from May to August, at about 15 to 20 °C. Climate change is raising temperatures and making both intense rain and dry spells more likely. Travellers can match this calendar to safaris and beach trips with our best time to visit Tanzania page.
How the Serengeti Wildebeest Migration Follows the Rain
The clearest sign of Tanzania's rainfall calendar is written across the Serengeti by about 1.7 million wildebeest, preceded by some 260,000 zebras and followed by around 470,000 gazelles. The herds move because the grass moves: they track the rain-ripened grazing in a clockwise loop between Tanzania and Kenya's Maasai Mara, and the journey from Tanzania to the Mara alone covers about 800 km.
From about January to March the herds graze the short-grass plains of the south-eastern Serengeti and the Ngorongoro Conservation Area, where rain-ripened grass is plentiful. In February roughly 500,000 calves are born within two or three weeks. As the long rains end in May, the animals head north-west towards the Grumeti River, where they usually stay until late June. Through the dry season they push north, crossing the Grumeti and Mara rivers from July and reaching Kenya in late July and August, where they remain until the grass fails. In early November, when the short rains return, the herds turn south again and are usually back on the southern plains by December. About 250,000 wildebeest die on the journey from thirst, hunger, exhaustion or predators. The herds' route is followed in more detail in our Great Migration guide.