In March, the weather in Mariehamn is typically cold. Average daily high temperature in March is about 2 degrees above zero. On average, Mariehamn has 11 partly cloudy, 8 cloudy, 6 rainy, and 6 sunny days in March. The rains are usually light. March as well as January, October, November, and December is considered the most uncomfortable time to visit Mariehamn.