Because of the great elevation gain on a Kilimanjaro trek, you will experience all kinds of weather – from hot to cold, wet to dry, sunny to stormy. The key is to be equipped so you can handle whatever the mountain throws at you.
There are five ecological zones that a climber will endure as he or she ascends. Each zone gets colder.
At the beginning of the climb, in the rainforest, expect it to be hot and humid. Most likely you will be comfortable wearing just a tee shirt and shorts or trekking pants while walking. It’ll probably be in the 70’s or 80’s in Fahrenheit, unless it is raining.
However, it gets cold pretty fast. Even on the first night of your climb, it will be chilly. A fleece jacket and knit hat will be required to keep you warm once the sun sets.
The following few days, as you make your way between campsites, most commonly you will be fine with just one or two layers on top, such as a base layer, a soft shell jacket and trekking pants. As long as you are moving, or in the sun, it is not cold. It’s actually quite comfortable. However, if you stop for an extended period of time, or the clouds come, or it’s windy, it will be cold. It is a good idea to either put on a fleece jacket or windbreaker when you stop for a break or when the temperature calls for it.
On every successively higher campsite, it will be colder. Most people like to hang out in camp wearing a down jacket and fleece pants. It frequently drops below freezing at night, meaning it is colder than 32F. You may wake up to ice crystals on the inside of your tent.
Some people make the mistake of trying to cover up the tent’s built in ventilation in order to keep cold air from entering the tent. But what this does is cause a build up of moisture in the tent. This actually makes you colder! The vents are there for a reason – do not mess with it!
On the summit night, it can be very, very cold, especially if there is wind. It can very well be zero degrees or colder. But more typical temperatures are about 20F-30F. Your guide will advise you what to wear. Most people seem to do well with four layers on top – base layer, soft shell, insulated jacket, hard shell, and three layers on bottom – tights, fleece pants, rain pants. Have a warm hat and warm gloves.
Once the sun comes up, it warms up fast. It can be below zero while you are on the way to the top, then as much as 30-40F in the morning sun. So remember to strip down and rid yourself of maybe two layers on top and a layer on the bottom for the descent or you will be sweating a lot. Don’t forget to drink water the whole time too.
I want to let you know that you should not be afraid of the cold. As long as you bring the right clothing, you will be fine. Don’t let an irrational fear of cold dissuade you from climbing.