In March, the weather in Uusikaupunki is typically cold. Average daily high temperature in March is about 1 degree above zero. On average, Uusikaupunki has 10 cloudy, 8 rainy, 6 sunny, 6 partly cloudy, and 1 snowy day in March. The rains are usually light. March as well as October, November, and December is considered the most uncomfortable time to visit Uusikaupunki.