December in Samui is the windiest month of the year. In December, the weather in Samui is typically warm. Average daily high temperature in December is about 27 degrees above zero. On average, Samui has 22 rainy, 4 sunny, 4 cloudy, and 1 partly cloudy day in December. The rains are usually heavy. December as well as May, June, July, and August is considered the most uncomfortable time to visit Samui.