October in Bay City is the rainiest month of the year. In October, the weather in Bay City is typically warm. Average daily high temperature in October is about 13 degrees above zero. On average, Bay City has 12 rainy, 8 sunny, 7 cloudy, and 4 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 Bay City.