Japan heat wave kills 7, triggers hyperthermia alerts in 25 prefectures

A severe heat wave has swept Japan, killing at least seven people and sending 4,580 patients to hospitals for hyperthermia or heatstroke between July 6‑12, according to the Fire and Disaster Management Agency. The number of ambulance transports more than tripled from the previous week, with 105 cases classified as serious.

The Ministry of the Environment and the Japan Meteorological Agency issued hyperthermia risk alerts for 25 prefectures, spanning Tohoku to Kyushu. Temperatures in many areas approached or exceeded 38 °C, and the heat‑index rose sharply, prompting officials to advise frequent water intake, use of air‑conditioning, and extra care for the elderly.

Tokyo’s government launched a "Cool Biz" campaign, urging public‑sector staff to wear short‑sleeved shirts and shorts to reduce office cooling loads and alleviate the heat. The measure, originally introduced in 2005, is part of broader energy‑saving efforts during the unusually hot summer.