If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Tlaxcala: The hottest months are usually April and May with an average temp of 62°F, while the coldest months are January and December with an average of 55°F. The rainiest months in Tlaxcala are September, June, August, and July, with each month seeing an average of 10 inches of rainfall.