August in Saint-Denis is the coldest month of the year. In August, the weather in Saint-Denis is typically warm. Average daily high temperature in August is about 22 degrees above zero. On average, Saint-Denis has 25 sunny, 4 rainy, and 2 partly cloudy days in August. The rains are usually light. August as well as June, July, and September is considered the most comfortable time to visit Saint-Denis.