September in West Palm Beach is the rainiest and the cloudiest month of the year. In September, the weather in West Palm Beach is typically hot. Average daily high temperature in September is about 29 degrees above zero. On average, West Palm Beach has 20 rainy, 9 sunny, and 1 cloudy day in September. The rains are usually heavy. September as well as June, July, August, and October is considered the most uncomfortable time to visit West Palm Beach.