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 16 degrees above zero. On average, Pemberton has 12 rainy, 12 partly cloudy, 5 sunny, and 1 cloudy day in September. The rains are usually heavy. September as well as June, July, and August is considered the most uncomfortable time to visit Pemberton.