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The great migration is not an event with a start date. It is a year-round loop of wildebeest, with zebra and gazelle alongside, following the rain and fresh grass around the Serengeti–Mara ecosystem, mostly in Tanzania and for a few months in Kenya. Its size is less certain than most pages suggest: aerial surveys have long put the wildebeest at over a million, but a 2025 Oxford-led satellite count suggested far fewer. Either way, the herds are vast, and the best time to see the great migration comes down to which part of that loop you want to stand beside.
This guide follows the herds month by month. For the Mara's own seasons and fees, see the best time to visit the Maasai Mara; for the Serengeti's regions, see the best time to visit the Serengeti.
The detail
Great migration dates, month by month
These are the usual dates for each stage.
| Month | Where the herds usually are | Country | What you see |
|---|---|---|---|
| January | Southern Serengeti and the Ndutu area | Tanzania | Herds on the short-grass plains; calving begins late in the month |
| February | Southern Serengeti and Ndutu | Tanzania | Calving at its peak — hundreds of thousands of calves within a few weeks — with predators often close by |
| March | Southern plains, starting to move | Tanzania | Calving tails off; long rains begin |
| April–May | Central Serengeti, moving north and west | Tanzania | Long columns on the move through green country; heaviest rain in April |
| June | Western corridor and the Grumeti River | Tanzania | Herds mass and cross the Grumeti; often around June, from about May to July |
| July | Northern Serengeti; first herds into the Maasai Mara | Tanzania and Kenya | First Mara River crossings in most years |
| August–September | Northern Serengeti and the Maasai Mara | Tanzania and Kenya | Crossings most likely; herds at their densest on both sides of the border |
| October | Maasai Mara and northern Serengeti | Kenya and Tanzania | Crossings continue, often back and forth; herds begin to turn south late in the month |
| November | Leaving the north, moving south through Lobo towards the central Serengeti | Tanzania | Return south as the short rains bring new grass |
| December | Spread across the central Serengeti, heading for the southern plains | Tanzania | Herds move south ahead of calving |
Rain drives the herds, and a wet or dry year can shift any stage by several weeks.
The Mara River crossings. The crossings are the migration's most famous chapter: herds build on the bank, sometimes for hours or days, before one animal commits and the rest follow through water where crocodiles wait. They happen on the Mara River on both sides of the border — around Kogatende in Tanzania's northern Serengeti and in Kenya's Maasai Mara — from about July to October, most often in August and September. A crossing can happen at any time of day, or not at all on a given day. The practical answer is time: plan several nights within reach of the river, rather than a single day trip. Which side to base yourself on is a park choice, covered in our Maasai Mara vs Serengeti guide.
Calving season. From late January to March, the herds gather on the southern Serengeti's short-grass plains and around Ndutu, and give birth within a few weeks of each other. February is the peak. It is less famous than the crossings but, for many people, more moving: newborns on their feet within minutes, predators working the edges of the herd, and far fewer vehicles than at the river in August. The weather is the short dry spell between the rains, usually warm and green.
The quieter middle chapters. April and May are the long rains, when the herds move through the central Serengeti and some seasonal camps close. June brings the Grumeti crossings in the western corridor — a smaller river, but a real crossing, and quieter than the Mara. These are good months if you want the herds without the peak-season crowds, and accept more rain or a less certain spectacle.
Watching well. At a crossing, vehicles crowding the bank can stop the herds: in August 2025 Kenyan rangers reported a Mara crossing halted when dozens of vehicles raced to the river. A good guide holds position at a distance and waits, rather than racing to the edge. In the Mara Triangle, the published park rules ask vehicles waiting for a sighting to stay 100 metres back, and limit viewing to 10 minutes when more than five vehicles are waiting. The same patience serves at calving: give mothers and newborns room.
A note for late 2026. Forecasters in Kenya and Tanzania expect heavier-than-usual short rains from October 2026, possibly lasting into January 2027, during a strong El Niño. That can change when the herds turn south and settle on the calving plains. For travel before February 2027, we plan around the latest forecast.
Key facts
River crossings: about July–October, most often August–September, in the northern Serengeti (Tanzania) and the Maasai Mara (Kenya). Calving: southern Serengeti and Ndutu, late January–March, peak February. Grumeti crossings: western corridor, often around June. Return south: about November. Herd size: contested — long estimated at over a million wildebeest; a 2025 satellite count suggested far fewer. Timing: follows the rain; any stage can shift by weeks. Late 2026: heavier short rains forecast, possibly into January 2027.
Planning it with Nobu
The herds do not follow a timetable, so the planning lies in hedging well: choosing the month with the best odds for the chapter you want, placing you within reach of where the herds tend to be, and giving you enough nights to let the animals decide. A travel designer weighs Kenya against Tanzania for your dates and tells you plainly when a month is the wrong one for what you hope to see.
Is it right for you?
August and September are right for you if a river crossing is the reason for the trip, you can commit several nights near the river, and you accept that this is the busiest time of the year. February is right for you if you want newborns, predators at work and the herds packed onto open short-grass plains, with fewer vehicles. April to June is right for you if you are happy with rain or smaller crossings in return for quiet. Choose something else if you have only two or three days and a single fixed week: the herds may not be where the calendar says, and a resident-game safari may serve you better. Our guide to the best time to go on safari covers timing beyond the migration.
Journeys to consider
- Tanzania, one chapter at a time. — Eight days through Tarangire, Ngorongoro and the Serengeti; ask us to time the Serengeti chapter to the herds. Tanzania, one chapter at a time.
- The Mara, unhurried. — Five days in one place, best from July to October, with time to wait for a crossing. The Mara, unhurried.
- Small-group journeys — Join a few other travellers and share the vehicle, the guide and the company. Small-group journeys
- A little wild. A little barefoot. — Nine days that begin in the Mara and end by the Indian Ocean. A little wild. A little barefoot.
