Donon, Spain offers 6 beaches perfect for sunbathing, surfing, swimming, and more. Donon, Galicia, Spain, is known for its scenic coastal landscapes and the ancient Celtic hill fort of Castro de Donón. The best time to travel to Donon, Spain, is in late spring or early fall when the average air temperature is around 70°F (21°C) and the water temperature is approximately 66°F (19°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!