Kilimanjaro can be climbed pretty much any day of the year, but most people choose to go during the dry seasons. During the rainy seasons, the paths at lower elevations can get slippery and muddy, and the upper part of the mountain can be snow covered.
The climate in northern Tanzania has two rainy seasons: the short rains in November, and the long rains from early March to mid-June. The peak seasons for climbing Kilimanjaro are the dry seasons from December to early March, and from mid-June to October.
The weather on Kili can be quite variable: our trip in early February should have been the dry season, but it rained a little every day, and the summit was covered in snow. Normally at that time of year it's so dry that some people wear bandanas over their mouths to avoid breathing dust on the trail!
Many people like to time their climb so that their summit day coincides with a full moon. Aside from some mystical significance, this means that the nighttime climb up to the summit is lit by the moon (as long as it's clear out!) We feel that Kili is busy enough on a normal day, so we would prefer to time the summit day for one or two days before or after the full moon. The moon will be almost full, but the crowds slightly less. Another option is to choose a route that takes you up to the summit during the day, instead of at night.
Upcoming full moon dates include: