October in Orillia is the rainiest month of the year. In October, the weather in Orillia is typically warm. Average daily high temperature in October is about 13 degrees above zero. On average, Orillia has 14 rainy, 7 sunny, 6 partly cloudy, and 4 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 Orillia.