Japan records its first ‘cruelly hot day’ as cities swelter in 40-degree heat

Japan’s meteorological agency coined the term kokushobi – or “cruelly hot day” to warn the public of dangers tied to extreme heat. Photograph: Nicolas Datiche/SIPA/Shutterstock View image in fullscreen Japan’s meteorological agency coined the term kokushobi – or “cruelly hot day” to warn the public of dangers tied to extreme heat. Photograph: Nicolas Datiche/SIPA/Shutterstock Japan records its first ‘cruelly hot day’ as cities swelter in 40-degree heat In April Japan coined new term kokushobi for days above 40C as country advises workers to wear shorts to the office to cope with stifling heat Japan logged its first official kokushobi or “cruelly hot day” on Tuesday since the new term for when temperatures top 40 degrees Celsius was introduced in April. The Japan Meteorological Agency coined the new designation to warn the public of the heat dangers of days that were once freak weather events but have now become more common. The central Japan cities of Gujo and Tajimi in Gifu prefecture, along with Toyota in Aichi prefecture, all hit 40C. Gujo’s 40C and Toyota’s 40.1C were all-time highs recorded at their respective weather stations. Alleged ice-cream cartel in Japan investigated as sweltering summer looms Read more Across 914 weather stations nationwide, 278 registered temperatures exceeding 35C or moshobi – “extremely hot days,” the highest level of warning until the recent introduction of the new terminology. Days over 25C are called natsubi or “summer days”, while those exceeding 30C are known as manatsubi – “true summer days.” On Monday, a man in his 40s was found dead on a street in Sanjo, Niigata prefecture, while another in his 70s died in Kanagawa, southwest of Tokyo. Both are believed to have succumbed to the heat. Heatstroke deaths topped 2,000 for the first time in 2024, while more than 100,000 people were taken to hospital last year between the beginning of May and late September, according to the fire and disaster management agency. The rising heat is affecting many aspects of Japanese life – including yields and the quality of rice, a staple. In response, farmers are planting more heat-tolerant varieties, while some are switching to crops such as avocado that have not traditionally been grown at scale in Japan. Impacts are also being seen in sport, with the most high-profile being the restructuring of the hugely popular koshien national high school baseball tournament. Played in the sweltering heat of August, the games have been split into morning and evening sessions since 2024 to reduce the chances of heatstroke for both players and spectators. ‘When I get home, my whole body aches’: extreme heat saps health and wages of India’s poorest workers Read more Meanwhile, office workers are being encouraged to wear shorts on hot summer days, the latest relaxing of Japan’s buttoned-down corporate culture as part of “Cool Biz” measures to reduce electricity consumption through lower use of airconditioning. Previous initiatives have encoura