December in Mae Sai is the coldest month of the year. In December, the weather in Mae Sai is typically warm. Average daily high temperature in December is about 22 degrees above zero. On average, Mae Sai has 15 partly cloudy, 11 sunny, 3 cloudy, and 2 rainy days in December. The rains are usually light. December as well as January and February is considered the most comfortable time to visit Mae Sai.