The Great Migration explained: where the herds are each month
A continuous circuit driven by rain, not a scheduled event.
About 1.3 million wildebeest move through this ecosystem, with zebra and gazelle alongside them. Nobody schedules it.
What it actually is
The Great Migration is not a single event. It is a continuous, year-round circuit by about 1.3 million wildebeest, with roughly 200,000 zebra and a large number of Thomson's gazelle moving on the same grass, between the southern Serengeti and the Maasai Mara in Kenya and back.
The herds are always somewhere. “Missing the migration” is not really possible — what is possible, and common, is being in the wrong part of a 30,000-square-kilometre ecosystem when they are four hundred kilometres away.
They move because they are following grass, and the grass follows rain. That is the whole mechanism, and it is also why nobody can give you a date.
Where the herds are, month by month
The pattern below holds in most years. It has been three weeks out in both directions in the years I have watched it.
| Months | Usually | What you would see |
|---|---|---|
| December to March | Southern Serengeti and Ngorongoro short-grass plains | Vast concentrations on open ground; calving from late January; very high predator activity |
| April to May | Dispersing, moving west and north-west | Long grass, spread-out herds, difficult viewing, heavy rain |
| June | Western corridor and the Grumeti river | Herds massing; the Grumeti crossings, which are smaller and far less visited than the Mara ones |
| July to September | Northern Serengeti and the Mara River | The famous crossings; also the busiest and most expensive camps in the country |
| October to November | Moving back south through the east | Thinner columns on the move; quiet, green, and underrated |
The river crossings
A Mara River crossing is the image that sells Tanzanian safaris, and it is worth being clear about what seeing one involves.
The herds mass at the bank, sometimes for hours, sometimes for days. Then something sets them off and a few thousand animals go across in a few minutes. There is no way to know on which day, at which crossing point, or at what hour. Guides read the gathering and get it right often enough to be worth paying for, and wrong often enough that three days in the north can produce nothing.
If a crossing is the point of your trip, the honest advice is: go in August or early September, stay at least four nights in the far north, and accept that you may still not see one. Anybody offering more certainty than that is guessing on your behalf.
What an operator cannot promise you
Any of it. Not a crossing, not a date, not a location. Our own journey pages say that your month makes certain things likely and others unlikely, and that is as far as honesty allows.
What we can do is tell you where the herds have usually been in your month, pick the camp accordingly, keep the itinerary loose enough to move, and say so plainly when your dates are poor for what you have asked for.
The trips that disappoint people are almost always the ones sold on a certainty nobody had.
Sources
Checked 6 November 2026. Anything that can change should be read at the source rather than trusted here.
- Tanzania National Parks (TANAPA) — Serengeti park information and regulations
- Tanzania Wildlife Research Institute — wildlife census and research, including migration monitoring
- Tanzania Meteorological Authority — rainfall, which is the only real predictor of where the herds go
Journeys this applies to
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