December in Chiang Rai is the coldest month of the year. In December, the weather in Chiang Rai is typically warm. Average daily high temperature in December is about 24 degrees above zero. On average, Chiang Rai has 18 partly cloudy, 10 sunny, 2 cloudy, and 1 rainy day in December. The rains are usually light. December as well as January is considered the most comfortable time to visit Chiang Rai.