Japan to Implement Revised Special Heatstroke Alert System Wed.

Tokyo, April 20 (Jiji Press)–Japan’s revised heatstroke special alert system will be introduced Wednesday, in response to potential dangerous heat conditions, with operations set to continue until Oct. 21. A heatstroke special alert, never issued since the original system was put in place in fiscal 2024, is announced on a prefectural basis when unprecedented heat is predicted. The revised system excludes from the target area 24 observation points, mainly at high altitudes, in 13 prefectures where the heat stress index has differed significantly from that of the prefectural capital over the past five years, with the aim of providing information that reflects actual conditions more accurately. Such sites include Karuizawa in Nagano Prefecture and Okunikko in Tochigi Prefecture, both located at high altitudes. The ministry will issue a special alert around 2 p.m. the previous day if the Wet Bulb Globe Temperature (WBGT) heat stress index, which is calculated on the basis of temperature, humidity and other factors, is forecast to reach 35 or higher at all observation points in the prefecture. A heatstroke special alert is one level higher than a heatstroke alert on the ministry’s heatstroke prevention scale. It calls for the cancelation or postponement of school and other events to be considered due to the risk of serious health damage. A heatstroke alert is to be issued when the WBGT index is expected to reach 33 or higher at even a single observation point within each of the country’s 58 forecast districts, with people urged to drink water frequently and use air conditioners. The frequency with which this alert is issued is increasing, reaching a record high 1,749 times in fiscal 2025. According to preliminary data from the health ministry, 1,521 people died of heatstroke in the country between May and September 2025. As elderly people are at high risk of heatstroke, the government is set to strengthen its countermeasures, including promoting welfare commissioner visits to the homes of elderly individuals. END [Copyright The Jiji Press, Ltd.]