The Ecuadorian coast operates on a two-season calendar that is the reverse of what most visitors expect. The rainy season (December through May) is also the warm, sunny season — water temperatures peak, the sea is calmer, and the beach is at its best. The dry season (June through November) brings cooler water, stronger winds, and a grey mist called the garúa that can settle for days.
The most important variable for Atacames is not climate but crowds. Ecuadorian school holidays and public holidays — Carnival (February/March), Semana Santa (April), and the July and August school break — bring the town to bursting. If you want the beach to yourself, come on a weekday between June and November and accept the cooler, mistier conditions.