Kastel Stafilic, Croatia offers 5 beaches perfect for sunbathing, surfing, swimming, and more. Kastel Stafilic is known for its historic Kastel Nehaj fortress and the 1500-year-old olive tree, one of the oldest in the world. The best time to travel to Kastel Stafilic, Croatia, is from June to September, when the average air temperature is around 25°C (77°F) and the sea temperature is approximately 24°C (75°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!