January in Kennewick is the cloudiest month of the year. In January, the weather in Kennewick is typically cold. Average daily high temperature in January is about 2 degrees above zero. On average, Kennewick has 20 cloudy, 9 rainy, and 2 sunny days in January. The rains are usually light. January as well as February, March, November, and December is considered the most uncomfortable time to visit Kennewick.