December in Rainbow Lake is the most freezing month of the year. In December, the weather in Rainbow Lake is typically freezing. Average daily high temperature in December is about 13 degrees below zero. On average, Rainbow Lake has 15 cloudy, 6 sunny, 6 partly cloudy, and 4 snowy days in December. The snowfalls are usually light. December as well as January, February, and April is considered the most uncomfortable time to visit Rainbow Lake.