Japan reveals new name for 40C-and-hotter days after blistering summer

Japan has introduced a new term, "kokushobi," to describe days when temperatures reach 40°C (104°F) or higher, following the country’s hottest summer on record. The term, which translates to "cruelly hot" or "brutally hot," was selected through a national online survey conducted by the Japan Meteorological Agency (JMA) that gathered nearly 478,000 responses. This new designation joins existing terms for days exceeding 25°C, 30°C, and 35°C, reflecting growing concerns over extreme heat events. The move comes after summer 2025 saw unprecedented temperatures across Japan, with the average nationwide temperature 2.36°C above the long-term average since records began in 1898. The country experienced nine days with temperatures exceeding 40°C, including a record 41.8°C in Isesaki city. Major urban centers also recorded significant increases in extremely hot days: Tokyo had 25 days above 35°C, compared to an average of 4.5, while Kyoto experienced 52 such days, far exceeding its average of 18.5. The introduction of "kokushobi" highlights the intensifying impact of climate change on Japan’s weather patterns, with heatwaves becoming more frequent and severe. The JMA forecasts a high likelihood of above-normal temperatures continuing through the summer months, underscoring the need for heightened public awareness and preparedness. This development aligns with broader global trends of escalating extreme weather events, including heatwaves, droughts, and floods, driven by climate change. By formalizing terminology for extreme heat, Japan aims to improve communication and public understanding of weather risks, potentially aiding in better heatwave response and mitigation efforts. The new term also reflects a cultural adaptation to the realities of a warming climate, emphasizing the urgency of addressing climate resilience and public health challenges.