Treen, United Kingdom offers 1 beach perfect for sunbathing, surfing, swimming, and more. Treen, England, United Kingdom, is known for the Minack Theatre, an open-air theatre perched on the cliffs above the Atlantic Ocean. The best time to visit Treen, United Kingdom, is during the summer months of June to August, when the average air temperature is around 18°C (64°F) and the sea temperature is approximately 16°C (61°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!