May in Trois-Rivieres is the rainiest month of the year. In May, the weather in Trois-Rivieres is typically warm. Average daily high temperature in May is about 16 degrees above zero. On average, Trois-Rivieres has 19 rainy, 7 sunny, and 5 partly cloudy days in May. The rains are usually heavy. May as well as April, October, and November is considered the most uncomfortable time to visit Trois-Rivieres.