Caister on Sea, United Kingdom offers 1 beach perfect for sunbathing, surfing, swimming, and more. Caister on Sea is known for Caister Castle and the Caister Lifeboat Station. The best time to travel to Caister on Sea, United Kingdom, is during the summer months of June to August, when the average air temperature is around 18-20°C (64-68°F) and the sea temperature is approximately 16-18°C (61-64°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!