Whanganui, New Zealand offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Whanganui is known for the Whanganui River, Whanganui National Park, and the Sarjeant Gallery. The best time to travel to Whanganui, New Zealand, is during the summer months of December to February, when the average air temperature is around 20-25°C (68-77°F) and the water temperature is approximately 19°C (66°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!