The best time to visit Tanzania

June to October. It is the dry season across most of the country, wildlife concentrates around the water that is left, the grass is short enough to see through, the roads are passable and the coast is reliable. If you are coming once, coming to see animals, and you can travel when you like, come then.

Everything else on this page is the long answer — because "best" depends on what you came for, and because the months that are best for wildlife are also the months that cost the most and carry the most vehicles. There is no month in which nothing is happening.

This is the thing most travel writing gets wrong, and it matters if your trip crosses the country. The Tanzania Meteorological Authority divides the country into two rainfall regimes:

Bimodal — two rainy seasons. The north, the north-eastern highlands, the northern coast, the Lake Victoria basin and Zanzibar. These get the long rains, Masika, from March to May, and the short rains, Vuli, from October to December. Between and after them are two dry spells.

Unimodal — one long rainy season. The centre, the south, the south-west and the west. These get a single season, Msimu, running from November through to April.

So a trip in November is the start of the short rains in the Serengeti and Zanzibar, and the start of the only rainy season in Ruaha and Katavi. A trip in January is comparatively dry in the north and wet in the south and west. "Is it the rainy season in Tanzania?" has no single answer.

Altitude matters as much as season here. The Serengeti and the Crater rim are cool at night year-round, the coast is hot and humid most of the year, and it can rain in the highlands in any month. Treat the table as the pattern, not a promise.

The migration. There is no month in which the herds are not somewhere. The crossings people picture happen in the north from roughly July to September; the calving happens in the south in January and February. The question is not when the migration happens but where it is this month — which is a page of its own: the Great Migration, month by month.

Kilimanjaro. Two windows: January to March, which is colder and quieter with a better chance of snow at the summit, and June to October, which is drier and busier. Climbing during the long rains is possible and miserable. See Kilimanjaro.

The beach and the reefs. Unguja, Pemba and Mafia are best from June to October and again from December to February. Avoid April and May, when the long rains are heaviest on the coast and some hotels close.

Whale sharks and whales. Whale sharks gather off Mafia from about October to March, most reliably between November and January. Humpback whales pass along the coast and through the Pemba and Zanzibar channels on their migration from the southern ocean, roughly July to September.

Birds. November to April is the best birding, when Palearctic migrants arrive and the resident species are breeding and in colour. It is the opposite of the best game-viewing season, which is why birders get the country cheap and empty.

Chimpanzees. Mahale and Gombe are at their best from May to October, when the forest trails are less slippery and the chimps are easier to follow.

Wildflowers. Kitulo — the "garden of God" — flowers from December to April, in the middle of the southern rains. It is the one place where the wet season is the season.

Every park page on this site carries its own best-months line, checked against that park's own sources. They are collected here so you can plan a route rather than a single stop. Note how many of the western and southern parks say the same thing — June to October — and how few exceptions there are.

The long rains, March to May, are the season nobody sells you. They are also the season with the strongest argument behind them if you are not on your first safari.

Prices fall steeply — green-season rates at the better camps can be half of August — the parks are close to empty of other vehicles, the light after a storm is the best of the year, and the country is green rather than the beige of October. Tarangire in the wet is a genuinely different park: the herds disperse, the grass grows and the birding is at its peak with over five hundred species recorded.

The costs are real. Some tracks become impassable and some camps in the southern and western parks close for part of the period, so check before booking. Game viewing is harder because water is everywhere and the animals no longer have to come to you. And Kilimanjaro in the long rains is a bad idea.

If you want the compromise: early June and late October sit on the shoulders of the dry season — most of the conditions, a fraction of the crowd, and noticeably lower prices.

The busiest weeks are July and August, and the fortnight around Christmas and New Year on the coast. In those periods the Ngorongoro descent road queues by mid-morning and the best camps sell out a year ahead. If you are travelling then, book early and stay on the Crater rim so you can go down at first light.

The quietest and cheapest months are April and May. March and November are the useful middle: mostly workable conditions, few people, and rates well below peak.

One thing that does not move with the season: park fees are set by the authorities, not by demand, and they are charged in US dollars. What changes with the season is the cost of beds and vehicles, which is most of the bill.