December in Seguin is the cloudiest month of the year. In December, the weather in Seguin is typically warm. Average daily high temperature in December is about 15 degrees above zero. On average, Seguin has 10 sunny, 8 rainy, 8 partly cloudy, and 5 cloudy days in December. The rains are usually light. December as well as January, June, and August is considered the most uncomfortable time to visit Seguin.