December in Sheffield is the windiest month of the year. In December, the weather in Sheffield is typically cold. Average daily high temperature in December is about 6 degrees above zero. On average, Sheffield has 15 rainy, 9 cloudy, 4 sunny, and 3 partly cloudy days in December. The rains are usually moderate. December as well as January, February, March, and April is considered the most uncomfortable time to visit Sheffield.