Opito Bay, New Zealand offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Opito Bay is known for its stunning beaches and proximity to the Mercury Islands. The best time to travel to Opito Bay, New Zealand, is during the summer months of December to February, when the average air temperature is around 24°C (75°F) and the water temperature is approximately 21°C (70°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!