Weather will likely play an important role when you plan your trip to Bontang, but bear 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 temperature of 27°C, while the coldest months are July and January, with an average of 27°C. The rainiest months in Bontang are December, January, April and November, with each month seeing an average of 312 mm of rainfall.