January in Oneonta is the coldest month of the year. In January, the weather in Oneonta is typically warm. Average daily high temperature in January is about 11 degrees above zero. On average, Oneonta has 11 sunny, 10 rainy, 5 cloudy, and 5 partly cloudy days in January. The rains are usually heavy. January as well as February, June, July, and August is considered the most uncomfortable time to visit Oneonta.