How we know: Sources are listed at the end. Weather figures are climate normals; migration, park and entry facts come from the cited travel-guide and government pages. Wildly does not publish fare averages in prose; live prices are on the linked route pages.
Kenya sits on the equator, so "best time" is less about temperature and more about rain, road conditions and where the wildebeest are. The short answer: the dry months from late June to October are the classic safari window and overlap with the Great Migration's time in the Maasai Mara; late December to mid-March is a second, greener dry season with good game viewing and fewer vehicles at the river crossings. The long rains of April–May are when lodges discount, roads flood and some camps close.
Nairobi weather by month
Climate normals for Nairobi (Jomo Kenyatta International Airport, elevation 5,300 ft), 1991–2020:
| Month | Avg high | Avg low | Rain | |---|---|---|---| | January | 80°F (27°C) | 57°F (14°C) | 2.3 in | | February | 81°F (27°C) | 57°F (14°C) | 1.4 in | | March | 82°F (28°C) | 59°F (15°C) | 2.9 in | | April | 79°F (26°C) | 60°F (15°C) | 5.1 in | | May | 77°F (25°C) | 59°F (15°C) | 4.3 in | | June | 75°F (24°C) | 56°F (13°C) | 1.1 in | | July | 74°F (24°C) | 53°F (12°C) | 0.4 in | | August | 75°F (24°C) | 54°F (12°C) | 0.7 in | | September | 79°F (26°C) | 55°F (13°C) | 0.7 in | | October | 80°F (27°C) | 58°F (14°C) | 2.0 in | | November | 78°F (25°C) | 60°F (15°C) | 5.1 in | | December | 78°F (26°C) | 59°F (15°C) | 3.4 in |
Highs barely move across the year; what changes is rain. April, May and November are the wet months, while July through September are close to bone dry. Nairobi's altitude keeps nights cool year-round (pack a fleece for dawn game drives), the coast around Mombasa and Diani is hot and humid all year, and the north is arid.
The two rainy seasons
Kenya has a "long rains" season from roughly April to June and a "short rains" season from October to December (Wikivoyage). Game viewing is best in the dry seasons between them: mid-June to October, and late December to mid-March. In the Maasai Mara specifically, Wikivoyage flags April–May and November as the months when parts of the reserve become "very muddy and practically inaccessible."
The short rains are usually brief afternoon storms rather than washouts, which is why November trips can still work, especially at the coast. The long rains are the ones to plan around.
Great Migration timing
The wildebeest migration is a year-round loop between Tanzania's Serengeti and Kenya's Maasai Mara, and the Kenyan leg is the shortest part of it. Wikivoyage's Kenya guide puts the migration in Kenya "between June and September," with July to September the best chances to see it; the Maasai Mara guide is more specific that the herds typically arrive "some time between July to early August" and begin to tail off by mid-September. Mara River crossings, the scene everyone wants, are concentrated in those weeks and draw crowds of vehicles.
The exact dates shift year to year with the rains, so if the crossings are the whole point of your trip, aim for August, book a camp near the river well in advance, and accept that no operator can guarantee a crossing on a given day. If you simply want big cats, elephants and full plains, any dry-season month delivers, and January–February in the Mara is excellent without the migration crowds.
Season by season
January–mid-March (short dry season). Warm, mostly dry, lush after the short rains. Good for the Mara, Amboseli (clearest views of Kilimanjaro), Samburu and the coast. Christmas and New Year are a peak for lodges; mid-January onward is calmer.
April–June (long rains). Heaviest rain in April and May, easing in June. Many lodges drop rates or close; roads in the Mara and Tsavo can be impassable. Birdlife and photography light are superb if you can tolerate the mud. The coast is at its most humid.
Late June–October (long dry season, peak). Cool, dry mornings, thin vegetation, animals concentrated at water. The migration is in the Mara from roughly July to September. This is Kenya's busiest safari season, and camps in the Mara book out months ahead.
November–December (short rains). Brief afternoon storms, green landscapes, lower prices until the Christmas rush. Coastal beach trips still work; the Mara is quieter.
Getting there from the US
Nairobi's Jomo Kenyatta International Airport (NBO) is the gateway for almost every US visitor, with Mombasa (MBA) reachable by a short domestic hop. According to the airport's destinations table, Kenya Airways operates the only nonstop US service, from New York–JFK. Everyone else connects: British Airways via London, KLM via Amsterdam, Air France via Paris, Qatar Airways via Doha, Emirates via Dubai, Turkish via Istanbul and Ethiopian via Addis Ababa all serve Nairobi, which means one-stop options from most large US airports.
The nonstop from JFK is roughly 14–15 hours; one-stop itineraries via Europe or the Gulf typically run 18–24 hours including the connection. For current prices see JFK to Nairobi, Chicago to Nairobi, Washington Dulles to Nairobi and LAX to Nairobi. Most safari itineraries add domestic flights from Nairobi's smaller Wilson Airport to Mara airstrips; your operator usually books these.
When fares tend to be lowest
Demand on US–Kenya routes peaks with the migration season (July–September) and again over Christmas and New Year, which is also when the US school and holiday calendars push transatlantic demand up generally. The long rains of April–May and the short rains of November are the quiet periods for both airfare and lodge rates, which is why "green season" safaris exist as a product.
That is a demand-calendar argument, not a price forecast. Fares on any given route move with capacity and competition, so pick your window, check the route page for what it is actually pricing today, and set a price alert with a target you would be happy to pay. Wildly checks the route daily and emails you when the fare drops.
Entry requirements for US citizens
Kenya abolished visas on January 1, 2024 and replaced them with a single-entry Electronic Travel Authorisation (eTA) that all foreign visitors, including US citizens, must obtain before travel (Wikivoyage, "Get in"). Apply online at the official portal, etakenya.go.ke; there is a fee, and approval is emailed to you, so apply at least several days before you fly and carry a printed or digital copy. A yellow fever vaccination certificate is typically required if you are arriving from or continuing to other African countries (Wikivoyage), and many travellers get the shot regardless; talk to a travel clinic about malaria prophylaxis, which is advised for the coast and most parks.
Where to go, by month
- January–February: Maasai Mara without the crowds, Amboseli for Kilimanjaro views, Diani Beach.
- March: Last dry weeks before the long rains; good value, warm.
- April–May: Green-season safari for photographers; expect mud and closures.
- June: Rains easing, landscapes green, migration not yet arrived; a good compromise.
- July–September: The Mara for the migration; Laikipia and Samburu as quieter alternatives.
- October: Still dry, herds heading south, fewer vehicles.
- November–December: Short rains; coast and Tsavo, then Christmas peak.
FAQ
When is the best month for the Great Migration in Kenya? August is the safest bet. Wikivoyage's Maasai Mara guide says the herds typically arrive between July and early August and tail off by mid-September; the Kenya guide gives July to September as the best chances.
Is Kenya worth visiting in the rainy season? Yes, with caveats. April–May brings the heaviest rain, mud and some closures, but also low prices, dramatic skies and newborn animals. November's short rains are lighter and rarely spoil a trip.
How cold does it get in Nairobi? Cooler than most people expect. July and August lows average around 53–54°F, and open-vehicle dawn game drives feel colder still. Bring layers.
Do I need a visa for Kenya? No visa, but you need an eTA approved before departure (etakenya.go.ke). Do not leave it to the airport.
Can I combine the coast and a safari? Easily. Domestic flights link Nairobi and the Mara airstrips with Mombasa, Malindi and Ukunda (Diani). Dry months suit both; the coast is hottest and stickiest from December to April.