Alnwick Haldimand, Canada offers 1 beach perfect for sunbathing, surfing, swimming, and more. Alnwick Haldimand, Ontario, Canada, is known for the Alderville First Nation and the scenic Rice Lake. The best time to travel to Alnwick Haldimand, Canada, is during the summer months of June to August, when the average air temperature is around 20-25°C (68-77°F) and water temperatures in nearby lakes are approximately 18-22°C (64-72°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!