Weather will likely play an important role when you plan your trip to Fomboni, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and December with an average temp of 82°F, while the coldest months are August and September with an average of 78°F. The rainiest months in Fomboni are January, February, March, and December, with each month seeing an average of 9 inches of rainfall.