Kenya has complicated and rather unpredictable weather patterns, making it harder to decide the best time to visit, and the impact of climate change is striking hard.
Broadly, the seasons are: hot and dry from January to March; hot and wet from April to June (the “long rains”). Warm and dry from July to October; and warm and wet for a few weeks in November and early December – a period called the “short rains”.
At high altitudes, it may rain at almost any time. Western Kenya, including the Maasai Mara, has a scattered rainfall pattern influenced by Lake Victoria, while the eastern half of the country, and especially the coast itself, are largely controlled by the Indian Ocean’s monsoon winds – the dry northeast monsoon (kaskazi) blowing in from November to March or April and the moist southeast monsoon (kusi) blowing in from May to October. The kusi normally brings the heaviest rains to the coast in May and June.
Temperatures are determined largely by altitude: you can reckon on a drop of 0.6°C for every 100m you climb from sea level. While the temperature at sea level in Mombasa rarely ever drops below 20°C, even just before dawn, Nairobi, up at 1660m, has a moderate climate, and in the cool season in July and August can drop to 5°C at night, even though daytime highs in the shade at that time of year easily exceed 21°C and the sun is scorching hot. Swimming pools are rarely heated, and only those on the coast are guaranteed to be warm.
The main tourist seasons tie in with the rainfall patterns: the biggest influxes of visitors are in December–January and July–August. Dry-season travel has a number of advantages, not least of which is the greater visibility of wildlife as animals are concentrated along the diminishing watercourses.
July to September is probably the best period, overall, for game-viewing, with early September almost certain to coincide with the annual wildebeest migration in the Maasai Mara. October, November and March are the months with the clearest seas for snorkelling and diving. In the long rains, the mountain parks are occasionally closed, as the muddy tracks are undriveable. But the rainy seasons shouldn’t deter travel unduly: the rains usually come only in short afternoon or evening cloudbursts, and the landscape is strikingly green and fresh even if the skies may be cloudy. There are bonuses, too: fewer other tourists, reduced prices and often perfect light for photography.
The main Christian religious holidays and the Muslim festival of Id al-Fitr are observed, as well as secular national holidays. Other Muslim festivals are not public holidays but are observed in Muslim areas. Local seasonal and cyclical events, peculiar to particular ethnic groups, are less well advertised.
On the coast, throughout the northeast, and in Muslim communities everywhere, the lunar Islamic calendar is used for religious purposes. The Muslim year has 354 days, so dates recede against the Western calendar by an average of eleven days each year. Only the month of fasting called Ramadan, and the festival of Id al-Fitr – the feast at the end of Ramadan, which begins on the first sighting of the new moon – will have much effect on your travels. In smaller towns in Islamic districts during Ramadan, most stores and hotelis are closed through the daylight hours, while all businesses will close in time for sunset, to break the daily fast. Public transport and most government offices continue as usual. Maulidi, the celebration of the prophet’s birthday, is worth catching if you’re on the coast at the right time, especially if you’ll be in Lamu, where it is celebrated in great style.
There are fewer music and cultural festivals than you might expect. Nairobi has a number of regular events, usually publicized on Facebook. On the coast, the Mombasa carnival used to take place in November, but has not happened for several years, but the Lamu Cultural Festival is a highly recommended regular fixture. Less than two hours west of Nairobi, Kenya’s first annual outdoor music festival, the Rift Valley Festival, has taken root on the shores of Lake Naivasha in late August and makes a great tie-in with a Maasai Mara migration safari. Finally, if you’re visiting in May, do everything possible to catch the extraordinary Lake Turkana Festival – a hugely enjoyable tribal gathering at Loiyangalani.
The Agricultural Society of Kenya (ASK) puts on a series of annual agricultural shows, featuring livestock and produce competitions, beer and snack tents, as well as some less expected booths, such as family planning and herbalism. These can be lively, revealing events, borrowing a lot from the British farming-show tradition, but infused with Kenyan style.