December in Udon Thani is the coldest month of the year. In December, the weather in Udon Thani is typically warm. Average daily high temperature in December is about 25 degrees above zero. On average, Udon Thani has 18 partly cloudy, 12 sunny, and 1 cloudy day in December. December as well as January is considered the most comfortable time to visit Udon Thani.