Duncan, Canada offers 1 beach perfect for sunbathing, surfing, swimming, and more. Duncan, British Columbia, Canada, is known for the Cowichan Valley's vibrant Indigenous culture and the world's largest collection of outdoor totem poles. The best time to travel to Duncan, Canada, is during the summer months of June to August, when the average air temperature is around 20-25°C (68-77°F) and the water temperature is approximately 15-18°C (59-64°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!