December in Jeju is the windiest month of the year. In December, the weather in Jeju is typically cold. Average daily high temperature in December is about 8 degrees above zero. On average, Jeju has 9 sunny, 8 rainy, 8 partly cloudy, and 6 cloudy days in December. The rains are usually light. December as well as January and February is considered the most uncomfortable time to visit Jeju.