Special Heat Stroke Alert ・ Heat Stroke Alert

Updated at Nov 3（Mon）5:00

Today［Nov 3］

Today［Nov 3］

Tomorrow［Nov 4］

Tomorrow［Nov 4］

This year's Heat Stroke Alert operation ended on October 22, 2025.

Heat Stress Index: WBGT

Provision of information on Heat Stress Index (WBGT) ended on October 22, 2025.

(Blue) Almost safe	(Sky) Caution	(Yellow) Warning	(Orange) Severe Warning	(Red) Danger
< 21 appropriate water replenishment suggested	21 - 25 water should be replenished often	25 - 28 rests should be provided often	28 - 31 heavy exercise prohibited	≥ 31 exercise prohibited

Note

WBGT index is one of the empirical indices representing the heat stress to which an individual is exposed. (ISO7243)
WBGT varies depending on environmental situation and condition.

Contents

• WBGT Guideline
• All about WBGT
• Heat illness prevention/countermeasures
• Materials
• Terms of Use