December in Thessaloniki is the windiest month of the year. In December, the weather in Thessaloniki is typically cold. Average daily high temperature in December is about 9 degrees above zero. On average, Thessaloniki has 16 sunny, 10 partly cloudy, and 5 rainy days in December. The rains are usually moderate. December as well as January, February, and March is considered the most uncomfortable time to visit Thessaloniki.