Lake Illawarra, Australia offers 1 beach perfect for sunbathing, surfing, swimming, and more. Lake Illawarra is known for its scenic lake views and water-based recreational activities. The best time to visit Lake Illawarra, 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!