October in Richmond Hill is the rainiest month of the year. In October, the weather in Richmond Hill is typically warm. Average daily high temperature in October is about 13 degrees above zero. On average, Richmond Hill has 14 rainy, 7 sunny, 5 cloudy, and 5 partly cloudy days in October. The rains are usually heavy. October as well as March, April, November, and December is considered the most uncomfortable time to visit Richmond Hill.