Tehuacan sits at around 1,700 metres in a semi-arid valley and has a mild, dry climate year-round. Temperatures rarely exceed 30°C or drop below 5°C at night. The rainy season runs from June through September — short afternoon downpours that clear quickly — but travel is rarely disrupted. The dry months from October through May are the most comfortable time to visit.
The hottest and driest months are March and April, when the cactus landscape looks most dramatic: stark, sun-bleached, and extraordinarily still. If you are visiting primarily to see the Tehuacan-Cuicatlán Valley, this is the best time — visibility is perfect and the roads south toward Zapotitlán Salinas are clear. The cactus blooms briefly in spring, usually April to May.
Semana Santa (Easter week) brings domestic tourists to the region and accommodation fills up; book ahead. The Feria de Tehuacan takes place in August and September, centring on the Día de San Miguel festivities at the end of September — the city's biggest annual celebration, with markets, processions, and music around the zócalo.