Mount Kenya has two dry seasons that are the best times to climb: January and February, and July through September. Conditions in these months are generally clear in the early morning, with cloud building through the day and clearing again before dawn — perfect for the standard pre-dawn summit attempt.
Avoid the long rains (March to May) and the shorter wet season (October to November). The mountain stays climbable in the rains but the Vertical Bog becomes a real ordeal and the views are usually obscured. Temperatures at the summit hover around freezing year-round; the lower forests are cool and pleasant.