Happou, Japan offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Happou, Tohoku, Japan, is known for the Shirakami-Sanchi, a UNESCO World Heritage Site featuring ancient beech forests. The best time to travel to Happou, Japan, is in late spring (May), when the average air temperature is around 18°C (64°F) and the water temperature is approximately 14°C (57°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!