March in Portland is the rainiest month of the year. In March, the weather in Portland is typically warm. Average daily high temperature in March is about 11 degrees above zero. On average, Portland has 26 rainy, 3 sunny, 1 cloudy, and 1 partly cloudy day in March. The rains are usually heavy. March as well as January, February, April, and November is considered the most uncomfortable time to visit Portland.