Japan endures first ‘kokushobi’ heatwave as temperatures exceed 40 °C, prompting alerts and deaths

Japan recorded its first officially designated “kokushobi” – a “cruelly hot day” – after three central cities (Gujo, Tajimi and Toyota) reached temperatures of 40 °C or higher on July 22. The Japan Meteorological Agency issued heat‑stroke alerts in 41 of 47 prefectures, urging residents to stay hydrated, use air‑conditioning and avoid prolonged outdoor activity. The Fire and Disaster Management Agency reported at least 14 heat‑related deaths and nearly 11,000 emergency visits in the past week, with thousands more hospitalized. Authorities are installing air‑conditioners in schools and urging workplace precautions. The extreme heat also affected recreational sites; climbers on Mount Fuji faced exhaustion and hypothermia risks despite the summer heat, and health experts noted a rise in “reibobyo,” a form of air‑conditioning sickness linked to rapid temperature changes. The event highlights the growing severity of Japan’s summer heat and its public‑health impacts.