The two main trekking seasons for Kilimanjaro correspond with the mountain’s two dry seasons namely January to mid-March and June to October. Of course you can walk in the rainy season, but not only is there a much higher chance of walking in the rain, but the summit is likely to be wreathed in thick cloud. Curiously, however, Christmas and New Year, when the weather is far from perfect, are actually the most popular times to go.
As to the relative merits of the two seasons, the differences are small though significant. The January to March season tends to be colder, and there is a much greater chance of snow on the summit at this time. The days, however, are often clearer, with only the occasional brief shower.
It is an exceptionally beautiful time to climb and is usually a little quieter than the other peak season of June to October, which coincides with the main academic holidays in Europe and the West.
In the June to October peak season, following the heavy rains of March to May, the clouds tend to hang around the tree-line. Once above this altitude, however, the skies are blue and brilliant and the chance of precipitation minimal (though still present).
Although this season tends to be busier, this is not necessarily a disadvantage. For example, if you are travelling alone to Tanzania but wish, for the sake of companionship or simply to cut down on costs, to join up with other travellers for the trek, then the high visitor numbers in the June-October peak season will give you the best chance of doing this. And even if you do crave solitude when you walk, it can still be found on the mountain during this peak season.
The trails are long, so you can always find vast gaps between trekkers to allow you to walk in peace; some of the routes - Rongai, for example, or the two trails across the Shira Plateau - almost never have more than one or two trekking groups on them at any one time, and are often completely deserted. And besides, Kilimanjaro is just so huge that its presence will dwarf your fellow trekkers, to the point where they become, if you wish them to be, quite unnoticeable.
Star gazing - Full moon
Having decided which period you wish to travel in, you may wish to refine your dates still further by timing your walk so that on the final push to the summit, which is usually conducted at night, you will be walking under the brightness of a full moon. Stargazers may also wish to coincide their trip with a major astronomical happening; the views of the night sky from Kili are, after all, quite exceptional.
