Weather will likely play an important role when you plan your trip to Bukit Lawang, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually June and July, with an average temperature of 27°C, while the coldest months are January and February, with an average of 25°C. The rainiest months in Bukit Lawang are November, December, October and September, with each month seeing an average of 377 mm of rainfall.