January in Riverdale is the windiest and the coldest month of the year. In January, the weather in Riverdale is typically warm. Average daily high temperature in January is about 12 degrees above zero. On average, Riverdale has 11 sunny, 9 rainy, 6 partly cloudy, and 5 cloudy days in January. The rains are usually heavy. January as well as June, July, August, and December is considered the most uncomfortable time to visit Riverdale.