December in Gdynia is the rainiest and the windiest month of the year. In December, the weather in Gdynia is typically cold. Average daily high temperature in December is about 2 degrees above zero. On average, Gdynia has 20 rainy, 7 cloudy, 2 sunny, and 2 partly cloudy days in December. The rains are usually moderate. December as well as February, March, and November is considered the most uncomfortable time to visit Gdynia.