Grad Krk, Croatia offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Grad Krk, Primorje Gorski Kotar, Croatia, is known for its historic Krk Cathedral and the Frankopan Castle. The best time to travel to Grad Krk, Croatia, is from June to September, with average air temperatures around 75°F (24°C) and water temperatures around 73°F (23°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!