December in Saint-Lo is the windiest month of the year. In December, the weather in Saint-Lo is typically cold. Average daily high temperature in December is about 8 degrees above zero. On average, Saint-Lo has 21 rainy, 4 sunny, 4 cloudy, and 2 partly cloudy days in December. The rains are usually moderate. December as well as January, February, and November is considered the most uncomfortable time to visit Saint-Lo.