Weather is probably a major factor when you plan your trip to Muong Thanh, and keep in mind that cheaper options are usually available when the weather isn’t as good. The hottest months are usually April and May with an average temp of 76°F, while the coldest months are January and December with an average of 64°F. The rainiest months in Muong Thanh are August, July, June, and May, with each month seeing an average of 15 inches of rainfall.