Japan recorded temperatures above 40 degrees Celsius for the fifth consecutive day on Saturday, the longest such streak since the Japan Meteorological Agency (JMA) began comparable records in 2010, according to the agency and multiple Japanese media outlets. The JMA has issued heatstroke alerts across most prefectures from Kanagawa south to Okinawa, urging the public to avoid unnecessary outdoor activity, stay hydrated and use air conditioning. The term “kokushobi” — meaning a brutally hot day — was introduced by the JMA in April for days when the mercury reaches 40 degrees or higher, though it triggers no official national action.

In the Tokai central region, all four prefectures — Shizuoka, Gifu, Mie and Aichi — recorded a kokushobi on Saturday, the JMA said. The city of Kofu in Yamanashi Prefecture became the first location outside Tokai to register a kokushobi this year. The previous record of four consecutive kokushobi days was set twice: from August 10 to 13, 2013, and from July 30 to August 2 last year, the agency noted. The highest temperature recorded during the current streak was 40.8 degrees in Mino, Gifu Prefecture, and 40.7 degrees in Tajimi, also in Gifu, according to Jiji Press.

Nearly 11,000 people received emergency medical care for heat-related conditions between July 13 and 19, the Fire and Disaster Management Agency reported, with 14 declared dead on arrival at emergency departments. The agency urged the public to treat the heatwave as a “disaster”. On Thursday, 453 people were hospitalised in Tokyo alone — a record since data collection began 16 years ago, according to the JMA. Japan records roughly 1,300 heat-related deaths annually and has set a target of halving that number by 2030.

Scientists attribute the increasing frequency and intensity of extreme heat episodes in Japan to human-caused climate change, according to reports from Japanese media. Last year Japan experienced its hottest summer on record, with the highest temperature of 41.8 degrees Celsius recorded on August 5, 2025, in Isesaki, north of Tokyo. The JMA forecasts highs of 38 degrees for Nagoya and Gifu on Sunday, with heatstroke alerts remaining in effect across most of the country.