Weather and Climate on Mt. Kenya
courtesy of Kenya Wildlife Service
There is a wide range of temperature on Mt. Kenya and can also be unpredictable; as a rough guide, it falls by an average of 5 C per 1000 vertical meters (3,421 ft) from the base of the mountain. Since cold air can hold less moisture, as the mountain air cools, it will lose its moisture as rain. Consequently, as the prevailing winds from the Indian Ocean, the eastern and south eastern slopes of the mountain tend to be the wettest; elevations above 4000 m (13,684 ft), are characteristically dry; and the summit of Batian at approximately 5200m (17,780 ft) is icy.
Although there are hikers and climbers on the mountain throughout the year, and despite global changes to the weather patterns, on average, there are two 'wet' periods: the 'long' rains from mid-March though to mid-June and the 'short' rains from mid-October through to mid-December. Allowing for the altitude, the time of the day, and rainfall, the mean temperature is relatively constant. On clear sunny days when hiking in shorts and a T-shirt can be very comfortable, as soon as the wind picks up or clouds and fog shroud the mountain, the temperature can rapidly drop to freezing. At altitudes above 3,500 meters, nighttime temperatures of more than 10 below Celsius is common.
Prevailing winds are from the south and east, and therefore those sides of the mountain received the highest rainfall; up to 2,500mm per year at 3,000m. Northern slopes receive the least rain, around 1,000mm annually. As one climbs higher the amount of precipitation decreases and at the base of the peaks it is less than 700mm annually.
Typically, the daily weather pattern is such that at dawn it is crystal clear and Mt. Kilimanjaro, 320 km away to the south can often be seen quite clearly from Point Lenana. After two or three hours of sunshine the ground heats up warming the air just above it which then begins to flow up the mountain and by ten a.m. clouds which formed at 2,000 m. have risen to 3,000 m. and by noon the whole mountain is often completely enveloped in clouds.
From then until early evening, rain, snow or sleet, depending on the altitude can be expected. In the evenings, as the temperature falls, the reverse happens. The ground surface and the air in contact with it become colder and the air begins to flow back downhill. The clouds begin to disappear starting from around the peaks and by eight p.m. are usually back below 3,000m. This phenomenon is known as the anabatic/katabatic effect. Highest wind speeds can be expected in the very early morning (during the height of downhill flow) and twelve hours later in mid afternoon (during the height of uphill flow). Visitors using tents are well advised to find a site protected from the downhill flow at night.
The Flora and Fauna of Mount Kenya
courtesy of Kenya Wildlife Service
Mt. Kenya is much more than a haven just for climbers and wildlife enthusiasts. Its eco-system is one of the few places where as many as 80, and possibly more, of the high altitude relic forms of plants which were once widely distributed during the Pleistocene period are endemic. The environment is so unique that the mountain is now both an International Biosphere Reserve and a World Heritage Site.
Mount Kenya contains about seven distinctive Ecosystem Zones:
 | Agricultural and Plantation Areas |
| Upland Gallery Forest |
| Bamboo Zone |
| Hagenia - Hypericum Parkland |
| Giant Heather Zone |
| Afro-Alpine Zone |
| Nival Zone |
