May in St-Lambert is the rainiest month of the year. In May, the weather in St-Lambert is typically warm. Average daily high temperature in May is about 17 degrees above zero. On average, St-Lambert has 20 rainy, 7 sunny, 2 cloudy, and 2 partly cloudy days in May. The rains are usually heavy. May as well as March, April, October, and November is considered the most uncomfortable time to visit St-Lambert.