March in Rio Grande is the rainiest month of the year. In March, the weather in Rio Grande is typically cold. Average daily high temperature in March is about 8 degrees above zero. On average, Rio Grande has 10 sunny, 9 rainy, 8 partly cloudy, and 4 cloudy days in March. The rains are usually moderate. March as well as January, February, and December is considered the most uncomfortable time to visit Rio Grande.