If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Tepotzotlán: The hottest months are usually April and May, with an average temperature of 18°C, while the coldest months are January and December, with an average of 14°C. The rainiest months in Tepotzotlán are August, July, September and June, with each month seeing an average of 186 mm of rainfall.