March in Missoula is the rainiest month of the year. In March, the weather in Missoula is typically cold. Average daily high temperature in March is about 3 degrees above zero. On average, Missoula has 26 rainy, 3 cloudy, and 2 sunny days in March. The rains are usually moderate. March as well as April and November is considered the most uncomfortable time to visit Missoula.