January in Sanya is the coldest month of the year. In January, the weather in Sanya is typically warm. Average daily high temperature in January is about 23 degrees above zero. On average, Sanya has 14 partly cloudy, 10 cloudy, 6 sunny, and 1 rainy day in January. The rains are usually light. January as well as February, March, and December is considered the most comfortable time to visit Sanya.