If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Chiltiupan: The hottest months are usually March and April with an average temp of 77°F, while the coldest months are January and December with an average of 75°F. The rainiest months in Chiltiupan are September, June, October, and May, with each month seeing an average of 10 inches of rainfall.