December in Sugar Land is the rainiest and the cloudiest month of the year. In December, the weather in Sugar Land is typically warm. Average daily high temperature in December is about 16 degrees above zero. On average, Sugar Land has 15 rainy, 8 sunny, 6 partly cloudy, and 2 cloudy days in December. The rains are usually heavy. December as well as June, July, August, and September is considered the most uncomfortable time to visit Sugar Land.