If you're hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Medjumbe Island: The hottest months are usually December and November with an average temp of 81°F, while the coldest months are July and August with an average of 76°F. The rainiest months in Medjumbe Island are January, February, March, and December, with each month seeing an average of 10 inches of rainfall.