September in St-Lambert is the sunniest month of the year. In September, the weather in St-Lambert is typically warm. Average daily high temperature in September is about 20 degrees above zero. On average, St-Lambert has 15 sunny, 7 rainy, 7 partly cloudy, and 1 cloudy day in September. The rains are usually heavy. September as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit St-Lambert.