September in La Romana is the cloudiest month of the year. In September, the weather in La Romana is typically hot. Average daily high temperature in September is about 31 degrees above zero. On average, La Romana has 19 rainy, 5 sunny, 4 partly cloudy, and 2 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 La Romana.