When you're travelling with pets, keeping track of the weather can help you make the trip more safe and fun for everyone. 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 12°C. The rainiest months in Chignahuapan are September, June, August and July, with each month seeing an average of 224 mm of rainfall.