January weather forecast in Plano

January in Plano is the coldest month of the year. In January, the weather in Plano is typically warm. Average daily high temperature in January is about 11 degrees above zero. On average, Plano has 18 sunny, 9 partly cloudy, 3 rainy, and 1 cloudy day in January. The rains are usually light. January as well as February, July, August, and December is considered the most uncomfortable time to visit Plano.