Playas Negras, El Salvador offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Playas Negras, La Union, El Salvador, is known for its unique black sand beaches and proximity to the Gulf of Fonseca. The best time to travel to Playas Negras, El Salvador, is from November to April, with average air temperatures around 85°F (29°C) and water temperatures near 82°F (28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!