Press Release

"Heat Stroke Alert" starts throughout Japan

April 23, 2021

(Tokyo, April 23) The Ministry of the Environment (MOE) and the Meteorological Agency announced that they will start, on April 28, 2021, the "Heat Stroke Alert", a helpline advising people on how to prevent heat illness. The Heat Stroke Alert will be operated when extremely high temperatures are predicted.


Over the last years, the number of patients transported by ambulance as a result of a heat illness has significantly increased. It is therefore important to raise awareness and provide guidance to prevent heat illness. MOE and the Meteorological Agency held research conferences with experts, and they implemented, in summer 2020, the Heat Stroke Alert trial in the Kanto and the Koshin regions when extremely high temperatures were predicted by the Wet Bulb Globe Temperature (WBGT)*. Considering the positive outcomes in both regions, the Heat Stroke Alert services will be operated nationwide from 2021.

*WBGT is a heat stress index estimating the risk of heat illness from the effect of direct sunlight, high temperature, humidity, and solar radiation.


Minister KOIZUMI Shinjiro declared:
Japan will strive to eliminate heat-related deaths. We are launching the "Heat Stroke Alert" and we will team up with local governments to run the "Heat Illness Prevention Campaign."


The outline of the Heat Stroke Alert is as follows:
(1) Announcement units
Japan is divided into 58 regions, and the Heat Stroke Alert will be announced by each region.
(2) Announcement standard
The Heat Stroke Alert will be announced when the WBGT index is above 33.
(3) Announcement time
The Heat Stroke Alert will be announced at 5:00 pm the previous day, and again at 5:00 am the following day, based on the latest available predictions.
(4) Term
The Heat Stroke Alert will be announced from the fourth Wednesday of April to the fourth Wednesday of October. In 2021, it is from 5:00 pm on April 28 to 5:00 am on October 27.
(5) Website of the Heat Stroke Alert
The MOE website will provide information on all announcements of the Heat Stroke Alert and WBGT index in each region.


Language: Japanese
(Computer)https://www.wbgt.env.go.jp/en/

(Smartphone)https://www.wbgt.env.go.jp/sp/

(Cell-phone)https://www.wbgt.env.go.jp/kt/


Environmental Health and Safety Division
Environmental Health Department
Ministry of the Environment, Japan
+81-3-5521-8259

For Japanese

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