December in Shirahama is the windiest month of the year. In December, the weather in Shirahama is typically cold. Average daily high temperature in December is about 5 degrees above zero. On average, Shirahama has 12 partly cloudy, 11 sunny, and 8 rainy days in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Shirahama.