May in Hays is the rainiest month of the year. In May, the weather in Hays is typically warm. Average daily high temperature in May is about 23 degrees above zero. On average, Hays has 13 sunny, 11 partly cloudy, 6 rainy, and 1 cloudy day in May. The rains are usually heavy. May as well as September and October is considered the most comfortable time to visit Hays.