Weather is probably a major factor when you plan your trip to Coatzacoalcos, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually May and April with an average temp of 82°F, while the coldest months are January and February with an average of 74°F. The rainiest months in Coatzacoalcos are September, August, July, and October, with each month seeing an average of 13 inches of rainfall.