July in Rio Mayo is the coldest month of the year. In July, the weather in Rio Mayo is typically cold. Average daily high temperature in July is about 5 degrees above zero. On average, Rio Mayo has 19 partly cloudy, 10 sunny, 1 rainy, and 1 cloudy day in July. The rains are usually light. July as well as May, June, August, and September is considered the most uncomfortable time to visit Rio Mayo.