Stanhope, Canada offers 5 beaches perfect for sunbathing, surfing, swimming, and more. Stanhope, Prince Edward Island National Park. The best time to travel to Stanhope, Canada, is during the summer months of July and August when the average air temperature is around 20°C (68°F) and the water temperature is approximately 18°C (64°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!