In May, the weather in Tehuacan is typically warm. Average daily high temperature in May is about 21 degrees above zero. On average, Tehuacan has 23 rainy, 4 sunny, 3 partly cloudy, and 1 cloudy day in May. The rains are usually heavy. May as well as June, July, August, and September is considered the most uncomfortable time to visit Tehuacan.