December in Pasco is the snowiest and the coldest month of the year. In December, the weather in Pasco is typically cold. Average daily high temperature in December is about 2 degrees above zero. On average, Pasco has 15 cloudy, 10 rainy, 4 sunny, 1 snowy, and 1 partly cloudy day in December. The rains are usually light. December as well as January, February, March, and November is considered the most uncomfortable time to visit Pasco.