Climate change is creating new words. Japan's Meteorological Agency (JMA) has created a new Japanese word. The word is "kokushobi". It means "cruelly hot day" or "harshly hot day". It will be used when describing days of 40ºC temperatures. There was an online poll to choose the new word. Website visitors selected their preferred word. There were 478,000 responses. The word kokushobi got nearly 203,000 votes.

Japan has had record-breaking weather, with days of 40ºC or above every year since 2018. In August 2025, a northern town recorded Japan's highest ever temperature. The mercury rose to 41.8ºC. There were nine more days of 40ºC temperatures. The year 2025 was Japan's hottest since records began in 1898. The Mainichi newspaper said that Kyoto recorded 52 days over 35ºC, compared with an annual average of 18.5 days.