January in Dover is the snowiest and the coldest month of the year. In January, the weather in Dover is typically freezing. Average daily high temperature in January is about zero. On average, Dover has 12 partly cloudy, 7 sunny, 5 cloudy, 4 snowy, and 3 rainy days in January. The snowfalls are usually moderate. January as well as February, March, May, and December is considered the most uncomfortable time to visit Dover.