Gujo City records first 40°C extreme heat day as Japan's heatwave trend persists

Three cities in central Japan have recorded temperatures exceeding 40°C, triggering the nation's new 'kokushobi' (cruelly hot day) warning classification for the first time. This event confirms an increasing frequency of extreme heat waves and a nine-year national trend of sustained extreme heat, with Gujo City in Gifu Prefecture recording its first 40°C day. The long-term impact on regional labor productivity and public health infrastructure remains to be quantified.