July in Riverdale is the hottest month of the year. In July, the weather in Riverdale is typically hot. Average daily high temperature in July is about 30 degrees above zero. On average, Riverdale has 13 rainy, 11 sunny, and 7 partly cloudy days in July. The rains are usually heavy. July as well as January, February, March, and August is considered the most uncomfortable time to visit Riverdale.