December in Sweetwater is the coldest month of the year. In December, the weather in Sweetwater is typically warm. Average daily high temperature in December is about 11 degrees above zero. On average, Sweetwater has 17 sunny, 13 partly cloudy, and 1 rainy day in December. The rains are usually light. December as well as January, June, July, and August is considered the most uncomfortable time to visit Sweetwater.