Weather will likely play an important role when you plan your trip to Bontang, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually October and May with an average temp of 81°F, while the coldest months are July and January with an average of 80°F. The rainiest months in Bontang are December, January, April, and November, with each month seeing an average of 12 inches of rainfall.