Weather is probably a major factor when you plan your trip to Phongsaly, 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 71°F, while the coldest months are January and December with an average of 59°F. The rainiest months in Phongsaly are July, August, June, and September, with each month seeing an average of 14 inches of rainfall.