September in Port Alsworth is the windiest month of the year. In September, the weather in Port Alsworth is typically warm. Average daily high temperature in September is about 9 degrees above zero. On average, Port Alsworth has 17 rainy, 5 cloudy, 4 sunny, and 4 partly cloudy days in September. The rains are usually heavy. September as well as January, May, June, and July is considered the most uncomfortable time to visit Port Alsworth.