July in San Luis Potosí is the rainiest month of the year. In July, the weather in San Luis Potosí is typically warm. Average daily high temperature in July is about 21 degrees above zero. On average, San Luis Potosí has 12 rainy, 8 partly cloudy, 7 sunny, and 4 cloudy days in July. The rains are usually heavy. July as well as August and September is considered the most uncomfortable time to visit San Luis Potosí.