Overview
- Three central cities reached 40°C on Tuesday, triggering the Japan Meteorological Agency’s new 'kokushobi' designation for days at or above 40°C.
- Heatstroke alerts cover 41 of 47 prefectures and the Fire and Disaster Management Agency urged the public to treat the event as a disaster after hospitals and ambulance services reported high demand.
- At least one heat-related death was confirmed when an 85-year-old man was found collapsed inside a greenhouse in Tochigi prefecture.
- The spike in temperatures followed a broad high-pressure system that warmed surface and upper-air layers and came after a later-than-usual end to the rainy season in parts of Honshu.
- The 'kokushobi' label was introduced in April to flag extreme danger above 40°C and sits above 'moshobi' (extremely hot day, ≥35°C); scientists link these intensifying summers to human-caused climate change and warn of sustained health and infrastructure strain.