December in Prince Rupert is the coldest month of the year. In December, the weather in Prince Rupert is typically cold. Average daily high temperature in December is about 2 degrees above zero. On average, Prince Rupert has 25 rainy, 5 sunny, and 1 cloudy day in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Prince Rupert.