Rosalie, Dominica offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Rosalie, Saint David, Dominica, is known for the Morne Trois Pitons National Park, a UNESCO World Heritage Site. The best time to travel to Rosalie, Dominica, is from December to April, with average air temperatures around 77-82°F (25-28°C) and water temperatures about 79-82°F (26-28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!