Summit temperatures on Mount Kilimanjaro (Uhuru Point) during the night can range between 20 and -20 degrees Fahrenheit (-7 to -29 degrees Celsius). It can also get down to -4 degrees Fahrenheit (20c) at Barafu lower down the mountain so you’ll want a sleeping bag that will keep you warm on frigidly cold nights no matter the season you plan on climbing.
The best sleeping bag for climbing Kilimanjaro will be rated to at least -20F to -30F that’s down (Down is lighter than Synthetic) and is a Mummy style bag.
Kilimanjaro guiding outfits will often recommend a synthetic sleeping bag like the Mountain Hard-wear Lamina Z Bonfire -30 Sleeping Bag rated to -30F. You can always unzip your sleeping bag if you get too hot, but it’s much harder to sleep comfortably in a sleeping bag that’s not warm enough.
You’ll also want to have the best sleeping pads to keep you warm when sleeping on cold ground. This sleeping pad combo is expedition worthy, the Therm-a-Rest Z Lite Sol Mattress along with the Therm-a-Rest Neo-Air Xtherm Sleeping Pad.