December in Riga is the windiest month of the year. In December, the weather in Riga is typically cold. Average daily high temperature in December is about 1 degree above zero. On average, Riga has 17 rainy, 9 snowy, 4 cloudy, and 1 sunny day in December. The rains are usually moderate. December as well as March, October, and November is considered the most uncomfortable time to visit Riga.