Weather will likely play an important role when you plan your trip to Khaem Son, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and March, with an average temperature of 28°C, while the coldest months are December and January, with an average of 24°C. The rainiest months in Khaem Son are August, July, May and September, with each month seeing an average of 450 mm of rainfall.