September in Saint Francois is the hottest month of the year. In September, the weather in Saint Francois is typically hot. Average daily high temperature in September is about 29 degrees above zero. On average, Saint Francois has 18 rainy, 11 sunny, and 1 partly cloudy day in September. The rains are usually heavy. September as well as May, August, October, and November is considered the most uncomfortable time to visit Saint Francois.