The best time to climb Kilimanjaro in Tanzania is from December to March and from July to October. The main rainy season falls in the months of April, May and June. The short rainy season is from mid-October to the end of November. In those months it is not the best time to travel to climb Kilimanjaro.
Preparation: make sure you are in good shape! It is possible to do this in the gym but a lot of walking as a backpacker is recommended. It is wise to take a rest the week before the hike, so that you start the trekking well rested. A good condition does not mean that you will not suffer from altitude sickness. That has no influence on this. Acclimatization is therefore ALWAYS necessary.
What are you taking with you? warm breathable clothing where you put on several layers of clothing in the beginning so that you have the opportunity to take it off and on. Bring dry clothes in the backpack packed in a plastic bag. Undergarments and (meri) woolen socks that dry quickly and are moisture regulating.
* thermal clothing
* walking shoes that are already broken in!
* balaclava or balaclave, gloves (nice and warm lined with fleece)
* paracetamol, sunscreen, mosquito repellent, lip balm
* head lantern
* light towels
* sleeping bag that is resistant to cold from – 20! and a sleeping mat
* ointment to treat bruises
* earplugs or mufflers
* binoculars
You can read all information about the prevention of altitude sickness and what it is at this page