If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Copan Ruinas: The hottest months are usually April and May with an average temp of 70°F, while the coldest months are January and December with an average of 65°F. The rainiest months in Copan Ruinas are September, June, August, and October, with each month seeing an average of 12 inches of rainfall.