March in Seattle is the rainiest, the windiest, and the cloudiest month of the year. In March, the weather in Seattle is typically warm. Average daily high temperature in March is about 10 degrees above zero. On average, Seattle has 24 rainy, 4 cloudy, and 3 sunny days in March. The rains are usually heavy. March as well as January, February, November, and December is considered the most uncomfortable time to visit Seattle.