December in Dinan is the windiest month of the year. In December, the weather in Dinan is typically cold. Average daily high temperature in December is about 9 degrees above zero. On average, Dinan has 16 rainy, 8 cloudy, 4 sunny, and 3 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 Dinan.