Porto Arthur, Brazil offers 1 beach perfect for sunbathing, surfing, swimming, and more. Porto Arthur is known for its beautiful beaches and vibrant local culture. The best time to travel to Porto Arthur, Brazil, is from May to September, when the average air temperature ranges from 20°C to 28°C (68°F to 82°F) and the water temperature is around 24°C to 26°C (75°F to 79°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!