In May, the weather in Dolbeau-Mistassini is typically warm. Average daily high temperature in May is about 14 degrees above zero. On average, Dolbeau-Mistassini has 17 rainy, 5 sunny, 5 partly cloudy, and 4 cloudy days in May. The rains are usually heavy. May as well as January, February, April, and October is considered the most uncomfortable time to visit Dolbeau-Mistassini.