September in Wasilla is the rainiest month of the year. In September, the weather in Wasilla is typically warm. Average daily high temperature in September is about 10 degrees above zero. On average, Wasilla has 14 rainy, 7 partly cloudy, 6 sunny, and 3 cloudy days in September. The rains are usually light. September as well as April, August, and October is considered the most uncomfortable time to visit Wasilla.