September in Laval is the sunniest month of the year. In September, the weather in Laval is typically warm. Average daily high temperature in September is about 19 degrees above zero. On average, Laval has 16 sunny, 8 partly cloudy, and 6 rainy days in September. The rains are usually moderate. September as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Laval.