If you're looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Tepeyahualco: The hottest months are usually May and April, with an average temperature of 19°C, while the coldest months are January and February, with an average of 14°C. The rainiest months in Tepeyahualco are September, August, June and July, with each month seeing an average of 322 mm of rainfall.