In April, the weather in Longueuil is typically warm. Average daily high temperature in April is about 10 degrees above zero. On average, Longueuil has 11 rainy, 7 partly cloudy, 6 sunny, and 6 cloudy days in April. The rains are usually heavy. April as well as March, May, October, and November is considered the most uncomfortable time to visit Longueuil.