Lake Jasper, Australia offers 1 beach perfect for sunbathing, surfing, swimming, and more. Lake Jasper, Western Australia, Australia, is known for D'Entrecasteaux National Park and its pristine freshwater lake. The best time to visit Lake Jasper, Australia, is during the summer months of December to February, when the average air temperature is around 25°C (77°F) and the water temperature is approximately 22°C (72°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!