You'll likely spend much of your trip indoors, but if you want to see more of the area, looking at local weather trends is a good idea. 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 Teotihuacan are August, July, September and June, with each month seeing an average of 176 mm of rainfall.