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 Tlaxcala: The hottest months are usually April and May, with an average temperature of 16°C, while the coldest months are January and December, with an average of 13°C. The rainiest months in Tlaxcala are September, June, August and July, with each month seeing an average of 257 mm of rainfall.