Portmellon, United Kingdom offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Portmellon, England, United Kingdom, is known for its picturesque Portmellon Beach and the nearby Lost Gardens of Heligan. The best time to travel to Portmellon, 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!