May in Trappes is the rainiest month of the year. In May, the weather in Trappes is typically warm. Average daily high temperature in May is about 17 degrees above zero. On average, Trappes has 19 rainy, 6 sunny, 3 cloudy, and 3 partly cloudy days in May. The rains are usually moderate. May as well as January, February, March, and November is considered the most uncomfortable time to visit Trappes.