January in Houston is the coldest month of the year. In January, the weather in Houston is typically warm. Average daily high temperature in January is about 12 degrees above zero. On average, Houston has 12 sunny, 9 rainy, 6 partly cloudy, and 4 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 Houston.