May in Windsor is the rainiest month of the year. In May, the weather in Windsor is typically warm. Average daily high temperature in May is about 18 degrees above zero. On average, Windsor has 15 rainy, 8 sunny, 6 partly cloudy, and 2 cloudy days in May. The rains are usually heavy. May as well as February, March, April, and November is considered the most uncomfortable time to visit Windsor.