December in Rahway is the cloudiest month of the year. In December, the weather in Rahway is typically cold. Average daily high temperature in December is about 6 degrees above zero. On average, Rahway has 12 partly cloudy, 7 rainy, 6 sunny, and 6 cloudy days in December. The rains are usually heavy. December as well as January, February, and March is considered the most uncomfortable time to visit Rahway.