Japan Records First 'Cruelly Hot Day' as Temperatures Exceed 40C in Multiple Regions

Japan’s meteorological office officially designated its first 'cruelly hot day' after temperatures rose above 40C in multiple locations. This new categorisation was established in April to highlight periods of extreme heat.

Isesaki, within Gunma Prefecture, saw the mercury reach 40.2C, making it the first area to meet the criterion since the designation's introduction. Other prefectures, including Saitama and Yamanashi, also recorded temperatures exceeding 39C, indicating widespread severe heat.

The agency’s new warning system classifies days over 30C as 'extremely hot' and those exceeding 35C as 'dangerously hot'. The 'cruelly hot' designation at 40C is intended to alert the public to life-threatening conditions.

This development underscores the increasing frequency and intensity of heatwaves in East Asia, prompting heightened concerns about public health and infrastructure resilience across the region.