December in Ishigaki is the windiest month of the year. In December, the weather in Ishigaki is typically warm. Average daily high temperature in December is about 21 degrees above zero. On average, Ishigaki has 19 rainy, 5 partly cloudy, 4 cloudy, and 3 sunny days in December. The rains are usually heavy. December as well as January, February, March, and May is considered the most uncomfortable time to visit Ishigaki.