December weather forecast in Portsmouth

December in Portsmouth is the windiest month of the year. In December, the weather in Portsmouth is typically cold. Average daily high temperature in December is about 9 degrees above zero. On average, Portsmouth has 18 rainy, 5 sunny, 5 cloudy, 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 Portsmouth.