Visiting local bars in Dien Bien Phu is better when you know what the weather holds. These rainfall averages and temperatures can help you decide the best time for bar hopping. 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 Dien Bien Phu are August, July, June, and May, with each month seeing an average of 15 inches of rainfall.