Postup, Croatia offers 1 beach perfect for sunbathing, surfing, swimming, and more. Postup, Dubrovnik Neretva, Croatia, is known for its renowned Postup wine, produced from the Plavac Mali grape variety. The best time to travel to Postup, Croatia, is from June to September, when the average air temperature is around 75°F (24°C) and the sea temperature is approximately 77°F (25°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!