The fact is most of the month have few rainy days makes it possible for climb relatively good condition all the year round. During the rain period of March and May, cloud tends to pile up and over the summit, dropping snow on top and at base. Visibility can be limited by cloud cover even when no rainfalls .The temperature at this time of the year is relative warm.
The dry season beginning in the rate June and through July can be very cold at night but usually is clear of cloud.
August and September are also cool and can have completely clear days, but usually a dripping cloud belt girdles the mountain above the forest moorland. The summit can be totally clear.
The shorter rainy period of October to December often has thunderstorms that pass over the mountain, dropping rains as they go. Typical the cloud disappear in the evening leaving the nights and morning very clear with excellent visibility.
January and February are usually dry, warm and clear with brief rain showers which make good climbing condition
Even though one can climb thought out the year, January, February and September are the best month with July, August, November and December are also good
We recommending Rongai route on trekking Mount Kilimanjaro in April and May which start on Northern Kilimanjaro and is generally drier than the southern route options during these months.
Kilimanjaro’s weather is heavily influenced by the interaction of trade winds with the structure of the mountain.
The South-East trade winds travelling over the Indian Ocean carry loads of moisture. When they hit Kilimanjaro, around March, then are forced upwards where they condense, form clouds and precipitation. This means March through to May is the wettest season on Kilimanjaro. The southern slopes are particular susceptible to rain during this time in the year.
Anti-trade winds from the North-East carry very little moisture but blow strongly. The strength of these winds which last from April through to October keep the South-east trade winds below them, hence these months are usually dry and cloud cover and precipitation is generally restricted to the lower slopes
The North-East monsoon arrives in November and brings some light rains to the Northern Kilimanjaro.
There are four distinct climatic zones on Kilimanjaro – the rainforest zone (800m-3,000m) is warm and humid. Rain is common in the zone, particularly during the wet season and temperatures average around 12-15 degrees Celsius at 2,870m. The second zone is often called the low alpine area (3,000m-4,200m) and is a semi-arid zone where average temperatures range between 5-10 degrees Celsius at 3,630m. The high alpine zone (4,200m-5,000) is desert-like. Here temperatures average around the freezing point at 4,970m, and at the summit in the glacial zone (above 5,000m) temperatures average around -6 degrees Celsius.