The Japan Meteorological Agency and the Ministry of the Environment issued the first heatstroke alerts of the year for wide areas including Kanto.
These alerts signal a critical increase in health risks as extreme heat spreads across the country. The warnings are intended to prompt immediate preventative action to avoid heat-related illnesses during a period of intensifying summer temperatures.
The alerts cover a broad region extending from southern Tohoku to Kyushu. In Nagano Prefecture, the forecast maximum temperature is 37 degrees Celsius [1]. Kanazawa City in Ishikawa Prefecture is expected to reach 36 degrees Celsius [2], while Tokyo is forecast to hit 34 degrees Celsius [3].
Officials said that these measures were necessary because severe heat has persisted nationwide. The combination of high temperatures and humidity increases the risk of heatstroke, a condition that can lead to severe dehydration or organ failure.
While the heat is the primary concern, the weather agency also warned of heavy precipitation in certain areas. Some regions are expected to see total rainfall exceeding 100 millimeters [4].
Residents in the affected areas are advised to stay hydrated and use air conditioning to maintain safe indoor temperatures. The government is monitoring the situation as the heatwave affects multiple prefectures simultaneously.
“Nagano is expected to hit 37 degrees Celsius.”
The early issuance of heatstroke alerts indicates an accelerating trend of extreme summer weather in Japan. By triggering these warnings in June, authorities are attempting to mitigate the burden on the healthcare system before the peak of the summer season, reflecting a growing public health priority to manage climate-driven temperature spikes.
