January in Houston is the coldest month of the year. In January, the weather in Houston is typically cold. Average daily high temperature in January is about 9 degrees above zero. On average, Houston has 11 sunny, 10 partly cloudy, 8 rainy, and 2 cloudy days in January. The rains are usually heavy. January as well as February, March, August, and December is considered the most uncomfortable time to visit Houston.