July in Dien Bien Phu is the rainiest month of the year. In July, the weather in Dien Bien Phu is typically warm. Average daily high temperature in July is about 26 degrees above zero. On average, Dien Bien Phu has 31 rainy days in July. The rains are usually heavy. July as well as April, May, June, and August is considered the most uncomfortable time to visit Dien Bien Phu.