March in Rapid City is the cloudiest month of the year. In March, the weather in Rapid City is typically cold. Average daily high temperature in March is about 7 degrees above zero. On average, Rapid City has 9 rainy, 8 cloudy, 8 partly cloudy, and 6 sunny days in March. The rains are usually moderate. March as well as February, April, and May is considered the most uncomfortable time to visit Rapid City.