Planning for the weather is a good way to make your trip to Tepoztlán relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and May with an average temp of 70°F, while the coldest months are January and December with an average of 61°F. The rainiest months in Tepoztlán are September, June, August, and July, with each month seeing an average of 10 inches of rainfall.