Weather will likely play an important role when you plan your trip to Pulau Bunaken, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and October with an average temp of 81°F, while the coldest months are February and March with an average of 79°F. The rainiest months in Pulau Bunaken are January, May, December, and November, with each month seeing an average of 13 inches of rainfall.