Weather will likely play an important role when you plan your trip to El Tunco, and keep in mind that cheaper options are usually available when the weather isn't as good. 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 El Tunco are September, June, October, and May, with each month seeing an average of 9 inches of rainfall.