Map from Google - Tanzania

Tanzania is a big African country, overlooking the Indian Ocean, lying just south of the Equator. The majority of the country is covered by a plateau, home to a large amount of world-famous tourist attractions, with several parks and nature reserves in the environment of the savannah. This plateau has a tropical climate, warm but tempered by the altitude. The thin flat coastal stretch is rather hot and humid throughout the year, especially from November to April.
As regards the rain pattern, the country can be divided into four zones. In the north and east, excluding the region of Lake Victoria, there are two rainy seasons: one less intense, known as short rains season between October and December, and the other more intense, known as long rains season from March to May, with the peak in April. In January and February, in the break between the two rainy periods, the weather is hot and sultry, at least below 3,000 feet. In the far north-west, the two rainy seasons are practically connected, because it rains even in January and February, when still from 4 to 6 inches per month fall, depending on the area: therefore in this area there is a single rainy season from October to May. Such a situation occurs occasionally also in some areas of the north-east, in particular along the southern slopes of Kilimanjaro. In the center and south, the rainy season is one, from December to April in the south and south-east, and from November to April in the west. The following map shows the months in which the rainy seasons occur in Tanzania, and also indicates if they are one or two.
Rainy seasons in Tanzania
The tropical rains occur mainly in the form of downpour or thunderstorm in the afternoon, so that in the morning the sky is often clear even during the rainy periods.

Dar es Salaam, the largest city and former capital of Tanzania, is located on the coast, in the area with two rainy seasons, and is hot all year round, with a slightly hotter and wetter period from November to April, when the maximum temperatures are around 89/90 °F, but with peaks of 95/97 °F, and minima around 73 °F, and high relative humidity, especially in March and April, the rainiest months. Here are the average temperatures.
Average temperatures - Dar Es Salaam
Dar Es SalaamJanFebMarAprMayJunJulAugSepOctNovDec
Min (°F)757373727066646464687073
Max (°F)909090888684848486888890

The annual precipitation amounts to 45 in, with a maximum from March to May; April is the rainiest month with 10 in. The period of the short rains, from October to December, is usually less pronounced, however, the rainfall pattern is quite irregular, so that in some years, even this period can be very rainy. From June to September there is little rain; this period, in addition to being the driest, is also the coolest, with highs around 84/85 °F and lows around 65 °F, but sometimes at night it can drop to around 59 °F. The amount of sunshine is good throughout the year, except during the long rains, from March to May.
Here is the average precipitation.
Average precipitation - Dar Es Salaam
Dar Es SalaamJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec. (in)32.25.5107.91.81112.84.94.745.3

The sea is always warm enough for swimming: the temperature ranges from 77 °F in August, to 84 °F in the summer months.
Sea temperature - Dar Es Salaam
Dar Es SalaamJanFebMarAprMayJunJulAugSepOctNovDec
Sea (°F)848484848281797779798284

Both climate and rain pattern are similar in the islands of Zanzibar, where, however, it rains more, about 65 inches per year in Zanzibar, and even 75 inches in the northern island of Pemba.

In the plateau, the temperatures vary with altitude, but the air is usually mild or warm without excess for most of the year. Rainfall tends to increase with altitude, but also depending on slope exposure and the proximity of the highest mountains, so that there are more or less rainy areas.

Dodoma, the capital of Tanzania, is located at 3,600 feet above sea level, in an inland dry area, and has a single rainy season. In an average year, only 24 in of rain fall, most of which occur from December to mid-April, while it almost never rains from May to October.
Here is the average precipitation.
Average precipitation - Dodoma
Prec. (in)

In October and November, before the rains, it can get hot, but peaks of 95 °F may occur until February. So the best time here goes from May to September, when the daytime temperature is about 80/84 °F, while at night it drops to around 56/58 °F, with some colder nights, around 46/50 °F.
Average temperatures - Dodoma
Min (°F)666664646357575759636466
Max (°F)848484848281818184888686

The climate is similar in Iringa, but it is a bit cooler since it is located at 4,600 feet above sea level, and therefore it's never excessively hot, and at night it can be a bit cold, especially from May to September.

In the north-east, in the area with two rainy seasons, we find a series of towering mountains, including Kilimanjaro, a volcano, 19.341 feet high, which is also the highest mountain in Africa, and has permanent snow above 16,500 feet, unfortunately in retreat because of global warming. Climbing the slopes we find different climates and biomes: between 6,000 and 9,200 feet, the rainforest; between 9,200 and 13,000 feet, where at night the temperature can drop below freezing, a dry mountain vegetation; between 13,000 and 16,500 feet, a cold desert, where, however, during the day the high altitude equatorial sun is very strong, warming considerably the bare rocks, while at night it gets very cold. On the top, which is often above the cloud layer, the night temperature may drop to -13/5 °F. Considering both the temperature (higher in January and February and lower from June to August) and precipitation (higher from March to June, lower from August to October), it's generally preferable to climb the mountain in January, February and September, while the worst months are April and May, due to the high rainfall (and even snowfall at high elevations), and frequent cloudiness. Some visitors choose the days of the full moon, which occur once per month, because the glaciers at night, illuminated by the moon, offer a wonderful sight.


West of Kilimangiaro, we find another mountain, the volcano Meru, 14,977 feet high. At the foot of Meru, the city of Arusha is located, at 4,600 feet of altitude. Here the temperature is pleasant all year round, so that the daily averages ranges from 66 °F in the period from January to April, to 57 °F in June and July. Sometimes, however, between November and March, during the day it can get hot. The nights are cool throughout the year, especially from June to September, when lows can drop below 50 °F, while during the day the temperature fluctuates around 68/72 °F.
Average temperatures - Arusha
Min (°F)505052555246484646505050
Max (°F)828281777270687275798181

The rainfall in Arusha amounts to 44 inches per year. Here is the average precipitation.
Average precipitation - Arusha
Prec. (in)

The Serengeti National Park is located north-west of Arusha, towards Lake Victoria and the border with Kenya; here the altitude varies between 3,600 and 6,500 feet. This is the area of the savanna, a kind of grassland becoming greener and higher in the rainy season, with rare trees such as giant baobabs, and animals such as rhinos, hippos, giraffes, elephants, lions, cheetahs and leopards. The driest part of the Serengeti, where the trees are a rarity, is the south-eastern one.
Here are the average temperatures at 5,000 feet above sea level.
Average temperatures - Serengeti
Min (°F)616161616159575959616161
Max (°F)848484828181798182848282

The Olduvai Gorge, the cradle of humankind, where fossil remains of early hominids were found, is located between the Serengeti and the Ngorongoro Conservation Area, at 4,600 feet above sea level. Here the climate is more arid.
On the contrary, the Ngorongoro Conservation Area is rainier, at least in the higher areas which exceed 6,500 feet. In the city of the same name, which lies at 8,000 feet, the weather is spring-like all year round, with cool nights, sometimes even a little cold, while the days are pleasantly warm from October to March, and mild from May to September. Here, as in the far north-west, some thunderstorms may occur even in the dry season, in January and February.
Average temperatures - Ngorongoro
Min (°F)505050525046464646485050
Max (°F)737372706866666870727272

In Tanzania there are several large lakes. In the north-west there is the huge Lake Victoria, at 3,600 feet above sea level, where the climate is warm all year round, as we can see from the temperatures of Mwanza.
Average temperatures - Mwanza
Min (°F)646464646461596163646464
Max (°F)828284828282828484848281

Here the rainfall amounts to 41 inches per year; we are in the area with a single rainy season, from October to May. Here is the average precipitation.
Average precipitation - Mwanza
Prec. (in)

Further south, Lake Tanganyika, along the Rift Valley, is located at 2,500 feet above sea level, and still further south, Lake Malawi is at 1,600 feet, therefore along its banks the weather is hotter due to lower altitude. Even in the center-south, there are several national parks and nature reserves.
Tanzania is too close to the Equator to be affected by tropical cyclones, because the Coriolis effect, which causes winds to swirl, at the Equator is zero.

When to go

The best time to visit Tanzania as a whole runs from July to August, being the coolest, the sunniest and driest. June is a good month almost everywhere, but in the north-east and in the island of Pemba, the long rains can linger on until this month. September is also a good month, but at lower elevations the days can be hot. In October, the season of short rains begins in the north, even though in the first half of the month in general there is little rain, but it can get hot at low altitudes.
In January, it rains a lot in the south, in the midst of the rainy season. Wanting to visit the country in the Northern Hemisphere winter (January and February), you can choose the northern areas, which in this period is in the break between the two rainy seasons, remembering that on the coast and at lower altitudes it's hot, and that some showers in the afternoon may still occur especially on the shores of Lake Victoria and in mountains like Kilimanjaro.
In the Serengeti you can go from June to September, with a preference for June, in the period of wildebeest migration through the rivers, before the animals move to Kenya, or even in January and February, to watch them in the southern part, towards the Olduvai Gorge.

What to pack

In inland areas, in general, it's better to dress in layers, warmer at high altitudes, lighter in the warm season and at low altitudes; sun hat, sunscreen, raincoat for the rain showers in rainy periods; for mountain climbing, hiking shoes. In parks and reserves, neutral-colored clothes, comfortable canvas shoes. For the summit of Kilimanjaro, throughout the year, cold weather clothing, synthetic thermal long underwear, fleece, parka, wind jacket, warm boots, sunglasses, sunscreen.
For the reef, equipment for snorkeling, water shoes or rubber soled shoes.

In winter (June to August): on the coast (Dar es Salaam, Zanzibar), light clothing, a sweatshirt for the evening, a light scarf for the breeze. On the shores of Lake Malawi and Tanganyika, light clothing, a sweatshirt and a light jacket, a light scarf for the breeze; in Arusha, Dodoma, Serengeti and Lake Victoria, light clothes for the day, sweater and jacket for the evening. In Ngorongoro and the plateau above 6,500 feet, spring/autumn clothes, with jacket and sweater; above 10,000 feet, warm jacket and hat.

In summer (December to February): on the coast (Dar es Salaam, Zanzibar), light clothing, made of natural fibers, a light sweatshirt for the evening, light raincoat or umbrella, especially in the south (see Mtwara). On the shores of Lake Malawi, Tanganyika and Victoria, and in Dodoma, light clothing, made of natural fibers, sun hat, a light sweatshirt for the evening, light raincoat or umbrella; in Arusha, Serengeti and the plateau at intermediate altitudes, you can add a jacket and sweater for the evening. In Ngorongoro and the plateau above 6,500 feet, spring/autumn clothes, with jacket and sweater, raincoat or umbrella; above 10,000 feet, down jacket and hat.