September in Pemberton is the windiest month of the year. In September, the weather in Pemberton is typically warm. Average daily high temperature in September is about 15 degrees above zero. On average, Pemberton has 14 rainy, 8 sunny, 5 partly cloudy, and 3 cloudy days in September. The rains are usually heavy. September as well as June, July, and August is considered the most uncomfortable time to visit Pemberton.