Climate at the shores of Lake Victoria is modulated by altitude, around 1,200 m, and by the moist winds coming from the Great Lakes. Temperatures are high during the day and moderate at night, with annual highs of 31°C and lows of 17°C.

At the slopes of Mount Elgon there are still some patches of tropical rainforest. The typical Highlands vegetation is found on the most part of this territory.

Rift Valley and Highlands

Speaking generally, altitude and winds in this region are the cause of a moderate and mild climate. In Nairobi, 1,700 m high, highest temperatures are 26-27°C in the boreal winter months and of 23°C during the boreal summer. The lowest are in the range of 12-15°C. Obviously, temperatures drop at higher altitudes. In the Mount Kenya region, mean temperatures are between 12 and 18°C, with night temperatures below 10°C. The night lows are equally cold in the Aberdare region. Rainfall is usually plentiful in the rainy season, with higher levels in the long rains.

The savannah, the most peculiar and typical lanscape in this region of the world, is actually nothing but a transition between rainforest and the arid steppe, and its origin as a natural or man-made ecosystem is controverted. It is mainly a grassland, dominated by gramineae and with variable presence of trees and bush, especially acacia. The savannah's natural balance is a consequence of the action of several factors: the regular rainfall pattern, which promotes the growth of tender pastures; migrations of large herds of herbivores, that move searching the young salt-rich pastures; and fire action, that hinders the overgrowth of trees and bush that would compete with grass for sunlight and the soil's nutrients.

Species of the Acacia genus, belonging to the Mimosa family, growing as tree or bush, are the most common and typical in the savannah. Acacias are easily distinguished by their flat top, their hard thorns, their composed leaves, their cylindrical clustering flowers and their leguminous-like fruit. Their bark is rich in tannin and is used for manufacturing dies and pharmaceutical products. The acacia is the favourite food for several animal species, such as giraffes, elephants and gerenuks.

The Highlands preserve, above 1,300 m, the richest extensions of rainforest in Kenya, though they do not exceed 3% of the total surface of the country. The largest patches are in Mount Kenya region. Ferns, mediterranean cedars, junipers and conifers of the Podocarpus genus are widely present. Bamboo forests are found above 2,000 m. At higher altitudes, above 3,000 m, mountain vegetation predominates, mainly heather, peat bogs, montane prairies and giant lobelias.

N, NE and Eastern Highlands (Nyika)

The northern and northeastern regions have the roughest climate, which is reflected in the arid landscape. Rainfall is scarce, with annual levels around 350 mm. Temperatures are high all the year round, rising to 37°C during the day in the hottest months. Night temperatures do not usually fall below 21°C. In the Eastern Highlands, temperatures are also warm but lower, around 30°C during the day and 20°C at night, with higher average rainfalls, specially in the areas surrounding Kilimanjaro.

Vegetation in the north and northeast is sparse, primarily consisting of thornbush. In the south area there are acacias and tree cacti of the Euphorbia genus. The giant Baobab (Adansonia digitata), of the Bombacacea family, outstands for its spectacularity, sometimes growing to 18 m high and with the trunks reaching 9 m in diameter. Its long and pulpy fruit is good for eating, and the bark is used for manufacturing ropes and cloth.

Vegetation is more diverse and abundant only at the oasis in the north and northeast, in the river valleys and in areas such as Taïta Hills, with an alpine-like landscape.

Given the extension of the arid regions, the biggest part of Kenya's land consists of deserts or semi-deserted steppes.

Kenya's coast

The average annual temperatures in the Kenyan Indian Ocean coast are around 28°C. In general, weather at the coast is warm and humid, as corresponds to its latitude. Storms are frequent and temperatures rarely drop below 21°C, with the highests around 32°C during the boreal winter months, which are generally drier and warmer. Total annual rainfall rises to 1,100 mm.

The temperature and humidity conditions make this region the suitable habitat for tropical vegetation. Mangroves and coconut palm trees grow along the shores and there are still some patches of tropical rainforest.