September in The Valley is the cloudiest and the hottest month of the year. In September, the weather in The Valley is typically hot. Average daily high temperature in September is about 28 degrees above zero. On average, The Valley has 21 rainy, 5 sunny, and 4 partly cloudy days in September. The rains are usually heavy. September as well as May, June, July, and August is considered the most uncomfortable time to visit The Valley.