Japan experiences 'cruelly hot days' with heatstroke alerts nationwide

Japanese cities are experiencing "cruelly hot days", a new meteorological term devised this year to warn people of intense heat above 40C, with heatstroke alerts issued across almost the whole country.

Three central cities on Tuesday logged scorching heat above the threshold, called "kokushobi" which translates to "cruelly hot day", according to the Japan Meteorological Agency.

On Wednesday, swathes of other areas, including the central hub of Nagoya and communities near Tokyo in the east, were enduring temperatures approaching or exceeding 40C.

The agency has issued heatstroke alerts in 41 out of Japan's 47 prefectures, urging the public -- especially the many elderly -- to take steps to stay cool.

In the rural Tochigi region, north of Tokyo, an 85-year-old man was found collapsed inside the greenhouse of his farm on Tuesday. He was later confirmed dead, a local fire spokeswoman told AFP.

"The greenhouse was extremely hot inside," she said.

The Fire and Disaster Management Agency on Wednesday urged the public to regard the extreme heat as a "disaster".

"Temperatures have been rising since mid-July, and severe heat is expected to continue nationwide," the agency said.

"It is no exaggeration to call this extreme heat a 'disaster' with many people being rushed to hospitals or even dying as a result of heatstroke," it said.

Scientists say human-induced climate change is increasing the frequency and intensity of extreme heat events in Japan and elsewhere.

Last year, the country sweltered through its hottest summer on record.

Japan's highest recorded temperature was recorded on August 5, 2025 when it hit 41.8C in Isesaki north of Tokyo.