January in Trier is the coldest month of the year. In January, the weather in Trier is typically cold. Average daily high temperature in January is about 2 degrees above zero. On average, Trier has 14 rainy, 12 cloudy, 4 sunny, and 1 partly cloudy day in January. The rains are usually moderate. January as well as February, November, and December is considered the most uncomfortable time to visit Trier.