May in Xam Neua is the warmest month of the year. In May, the weather in Xam Neua is typically warm. Average daily high temperature in May is about 26 degrees above zero. On average, Xam Neua has 30 rainy and 1 sunny day in May. The rains are usually heavy. May as well as April, June, July, and August is considered the most uncomfortable time to visit Xam Neua.