January in Osterode am Harz is the snowiest, the cloudiest, and the coldest month of the year. In January, the weather in Osterode am Harz is typically cold. Average daily high temperature in January is about 1 degree above zero. On average, Osterode am Harz has 15 rainy, 9 cloudy, 5 snowy, and 2 sunny days in January. The rains are usually moderate. January as well as February, March, October, and November is considered the most uncomfortable time to visit Osterode am Harz.