September in Basse-Terre is the hottest month of the year. In September, the weather in Basse-Terre is typically hot. Average daily high temperature in September is about 29 degrees above zero. On average, Basse-Terre has 16 rainy, 11 sunny, 2 partly cloudy, and 1 cloudy day in September. The rains are usually heavy. September as well as May, July, October, and November is considered the most uncomfortable time to visit Basse-Terre.