The Great Migration keeps no calendar. It is a loop, a slow circuit of the Serengeti-Mara ecosystem made by roughly one and a half million wildebeest, with zebra and gazelle moving alongside, all following the rain and the grass it brings. It has no start, no finish and no schedule. What it has is a rhythm, and the rhythm is worth learning before you choose a month.
In brief
- January to March: the calving season. Newborns and the predators who follow them, on the southern plains. February is the peak.
- June to October: the dry season. The traditional window for the migration as a whole, and the one Tanzania National Parks recommends. The herds drift north and west.
- Late July to early November: the northern Serengeti and the Mara River. The herds gather at the river and cross it, sometimes into Kenya. No one can promise a crossing on a given day.
The year, season by season
January to March: the plains and the newborns
With the early rains the herds settle on the short-grass plains of the southern Serengeti and the Ngorongoro Conservation Area, around Ndutu. Here, in a few weeks, up to about half a million calves are born. Most arrive within roughly three weeks, in January and February, a timing that scientists have long read as a defence in numbers: when every calf is born at once, predators cannot take them all. Calves stand within minutes and run with the herd within days. It is also the season of lions, hyenas and cheetahs on open ground.
April to June: the turn north
As the plains dry, the herds gather and begin moving north-west, toward the Moru Kopjes and Seronera. The rut, the breeding season, peaks around May and June. The movement can be gradual, then sudden, depending on the rain.
June to July: the Western Corridor
The herds reach the Western Corridor and the Grumeti River, where crocodiles are the first great test of the journey.
Late July to early November: the north and the river
This is the season most people picture. The Mara River is the dry-season lifeline for about 1.3 million wildebeest, and the herds gather in the northern Serengeti and cross toward the Masai Mara. Collared wildebeest have been recorded crossing only in the dry season, and mostly when the river is low. Crossings are driven by the rains, the herd's nerve and the state of the river, so watching often means waiting, and some days bring no crossing at all.
October to December: south again
The herds turn south and spread across the eastern and southern Serengeti, and the circuit begins again.
A note on certainty
The Serengeti's own researchers are frank about this. The 2023 census, run by the Serengeti Biodiversity Program with the Tanzania Wildlife Research Institute, Tanzania National Parks and Frankfurt Zoological Society, estimated about 1.37 million wildebeest, with a wide margin of error, and found no significant change over two decades. Their monitoring also reports that in 2021 only 5 of 28 collared wildebeest crossed the Mara River, where in earlier years all had.
So the calendar is a guide, not a guarantee. Rainfall shifts the herds. A crossing typical of August can come earlier, later, or elsewhere. The migration is many groups moving at different speeds, so you can see great herds and still miss the crossing. And the peak months are busy: Tanzania National Parks advises booking accommodation early for peak migration periods.
Choosing your time
What do you most want to see? Newborn calves and predators point to February. The river points to the dry season in the north. The open plains and the full sweep of herds point to the months between.
How fixed are your dates? If your dates are set, that shapes which part of the Serengeti makes sense, and it is worth raising at the start.
How do you feel about not knowing? Wildlife keeps its own time. The aim of good planning is to give you more chances, not a promise.
The Great Migration & Island Escape
On the Great Migration & Island Escape, ten days from Tarangire to Zanzibar, the Serengeti is the middle act: a night in the central Serengeti, then two nights in the north, with the herds followed wherever they are. As with every Serengeti journey, migration movements and river crossings remain seasonal and unpredictable. Then the journey leaves the plains for the ocean: two nights at Nungwi, on Zanzibar.
Tell us when you hope to travel.