September in Valemount is the sunniest month of the year. In September, the weather in Valemount is typically warm. Average daily high temperature in September is about 10 degrees above zero. On average, Valemount has 14 rainy, 10 sunny, and 6 partly cloudy days in September. The rains are usually moderate. September as well as April, May, June, and July is considered the most uncomfortable time to visit Valemount.