Japan Weather TodayHeatstroke alerts in Japan
Japan's summers are hot and humid. Get the official heatstroke alerts and simple advice in English.
- Japan issues heatstroke alerts (熱中症警戒アラート) for each prefecture when dangerous heat is expected.
- The app shows the alert for your area on the Local and Alerts tabs, with what to do: stay somewhere air-conditioned at midday, drink water often and take some salt.
- Daily tips also cover strong UV, humidity and when it is a good time to be outside.
- Heatstroke alerts are most common from July to September.
Everything else in the app
- Hour-by-hour forecast with rain timing, feels-like temperature, UV and daily tips.
- Rain radar from JMA, 3 hours back and 15 hours ahead, plus live Himawari satellite clouds.
- Official warnings: heavy rain, heatstroke alerts, earthquakes, tsunami and typhoons, in plain English.
- Trip planner: the weather for every stop of your trip, and ideas for sunny days, rainy days and food.
- Road trips: every service area, parking area and 道の駅 on your route, with the weather on arrival.
- 7 languages: English, 日本語, Deutsch, Français, Italiano, Español, with romaji under Japanese names.
Questions
Is the heatstroke alerts in japan free?
Yes. Japan Weather Today is free, with no sign-up and no ads. It runs in your browser on phone or computer.
Where does the data come from?
Official warnings, radar and typhoon data come from the Japan Meteorological Agency (JMA). Forecasts come from Open-Meteo, which blends national weather models including JMA's.
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