January in Lạng Sơn is the coldest month of the year. In January, the weather in Lạng Sơn is typically warm. Average daily high temperature in January is about 14 degrees above zero. On average, Lạng Sơn has 15 cloudy, 11 rainy, 4 sunny, and 1 partly cloudy day in January. The rains are usually moderate.