September in Ponce is the rainiest month of the year. In September, the weather in Ponce is typically hot. Average daily high temperature in September is about 30 degrees above zero. On average, Ponce has 25 rainy, 3 sunny, and 2 partly cloudy days in September. The rains are usually heavy. September as well as April, May, June, and July is considered the most uncomfortable time to visit Ponce.