Japan Debuts “Kokushobi” After 3 Cities Hit 40°C in First Use of New Heat Alert
Updated
Updated · The New York Times · Jul 23
Japan Debuts “Kokushobi” After 3 Cities Hit 40°C in First Use of New Heat Alert
3 articles · Updated · The New York Times · Jul 23
Summary
Three central Japan cities triggered the first official use of “kokushobi” on Tuesday after temperatures reached 40°C or higher, prompting authorities to urge people to stay indoors, use air-conditioning and drink water.
The Japan Meteorological Agency created the label—meaning “cruel heat day”—after record heat-stroke cases last year and repeated city temperature records showed numeric warnings alone were not cutting through.
More than 400,000 people voted in a public poll earlier this year, with “kokushobi” winning over 40% support against alternatives such as “dangerously hot day” and “sauna day.”
Osaka Castle and Kyoto’s Kiyomizu Temple saw lighter crowds on Tuesday, an early sign the new wording may be helping people treat 40°C heat as a distinct public-health danger.
Japan has new heat alerts, but are its cities truly ready for a future where 40°C summers are the new normal?
With 'cruelly hot' days now official, is Japan's culture of endurance being replaced by a new reality of climate adaptation?
As extreme heat threatens Japan's iconic rice crops, how will the nation's food security and culinary traditions be forced to adapt?
"Japan’s 40°C ‘Kokushobi’ Days: Extreme Heatwave Forces New Health Alerts and Societal Change"
Overview
In July 2026, Japan experienced its first 'kokushobi' days, a new term officially adopted in April to describe days when temperatures reach or exceed 40°C—now a frequent occurrence. This change reflects a clear shift in Japan’s climate, making previous heat categories insufficient. The term was chosen through a public survey with nearly half a million responses, showing widespread concern about rising temperatures. The introduction of 'kokushobi' and strong public engagement highlight how Japan is recognizing and responding to its escalating heat crisis, marking a significant moment in the country’s adaptation to extreme weather.