January in Slupsk is the snowiest, the windiest, and the coldest month of the year. In January, the weather in Slupsk is typically cold. Average daily high temperature in January is about 1 degree above zero. On average, Slupsk has 10 cloudy, 9 partly cloudy, 8 rainy, 3 sunny, and 1 snowy day in January. The rains are usually moderate. January as well as February, March, April, and October is considered the most uncomfortable time to visit Slupsk.