January in San Luis is the rainiest and the hottest month of the year. In January, the weather in San Luis is typically hot. Average daily high temperature in January is about 31 degrees above zero. On average, San Luis has 17 sunny, 11 rainy, and 3 partly cloudy days in January. The rains are usually heavy. January as well as February, November, and December is considered the most uncomfortable time to visit San Luis.