Planning for the weather is a good way to make your trip to Bukit Lawang relaxing and enjoyable, especially when you're splurging. 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.