December in Sasebo is the windiest month of the year. In December, the weather in Sasebo is typically warm. Average daily high temperature in December is about 10 degrees above zero. On average, Sasebo has 14 rainy, 8 sunny, 7 partly cloudy, and 2 cloudy days in December. The rains are usually moderate. December as well as January, February, June, and July is considered the most uncomfortable time to visit Sasebo.