Japan Introduces “Kokushobi” to Flag Extreme Heat

The Japan Meteorological Agency (JMA) launched a new public warning label, “kokushobi” (cruel heat day), to denote days when temperatures reach 40 °C (104 °F) or higher. The term was chosen through a nationwide poll that attracted more than 400,000 votes. Over 40 percent of participants selected “kokushobi,” beating a dozen alternatives such as “dangerously hot day” and “sauna day.” The label was applied for the first time when three central-Japan cities simultaneously recorded 40 °C, prompting officials to urge residents to stay indoors, use air-conditioning, and stay hydrated.

New York Times

Last year saw a surge in heat-stroke incidents, the highest on record, as an unprecedented number of Japanese cities logged their hottest temperatures ever. Health and weather authorities reported that the spike occurred despite earlier official warnings about the dangers of excessive heat.

New York Times

The JMA’s poll, conducted in February and March, enlisted input from meteorologists, media professionals, and linguistics experts to compile a shortlist of candidate names. The public’s preference for “kokushobi” reflected a desire for a clear, emotionally resonant term that could cut through numeric data and convey immediate risk.

New York Times

Following the first “kokushobi” designation, the agency’s advisories emphasized indoor shelter, air-conditioning use, and regular water intake. Preliminary observations indicated that popular tourist sites such as Osaka Castle and Kyoto’s Kiyomizu-dera Temple experienced noticeably lighter crowds, suggesting that many people heeded the warning.

New York Times

“Numbers are difficult to understand because people perceive them differently. By giving it the name ‘cruel heat day,’ people will understand it better just by hearing it, and they’ll feel that today is dangerous,” — Taro Kawasato, the assistant director of the Japan Meteorological Agency’s climate prediction division

New York Times