May in Sheridan is the rainiest and the cloudiest month of the year. In May, the weather in Sheridan is typically warm. Average daily high temperature in May is about 14 degrees above zero. On average, Sheridan has 13 rainy, 7 sunny, 6 partly cloudy, and 5 cloudy days in May. The rains are usually heavy. May as well as January, February, March, and April is considered the most uncomfortable time to visit Sheridan.