May in Seguin is the rainiest month of the year. In May, the weather in Seguin is typically hot. Average daily high temperature in May is about 30 degrees above zero. On average, Seguin has 12 rainy, 8 sunny, 8 partly cloudy, and 3 cloudy days in May. The rains are usually heavy. May as well as June, July, August, and September is considered the most uncomfortable time to visit Seguin.