Three locations in Japan recorded temperatures above 40°C on July 21, triggering the first "酷暑日" (extreme-heat day) designations since the system began this year [1], [2].
This milestone marks the first time the Japan Meteorological Agency has deployed this specific classification since its 2026 implementation. The designation serves as a critical alert for disaster-level heat that poses immediate risks to public health and infrastructure.
The temperatures were recorded in Toyota City in Aichi Prefecture, and in Tajimi and Gujo Hachiman in Gifu Prefecture [1], [2]. According to the Japan Meteorological Agency, the heat was caused by a Pacific high-pressure system that blanketed the country in warm air [1].
"Extreme-heat days" are officially announced when temperatures of 40°C or higher are observed [1]. The agency said the combination of the high-pressure system and warm air led to the three locations exceeding that threshold [1].
Officials warned that the dangerous weather is not over. The agency said that because the country remains covered in warm air this week, disaster-level heat is expected to continue on July 22 [1].
While some reports earlier this month suggested similar temperature spikes in other regions, official data for July 21 confirmed only these three specific sites reached the 40°C mark [2]. The agency continues to monitor the Pacific high-pressure system as it influences national weather patterns during the peak of the summer season.
“Three locations in Japan recorded temperatures above 40°C on July 21”
The activation of the 'extreme-heat day' designation indicates that Japan is now treating 40°C thresholds as a distinct category of meteorological disaster. By separating these events from standard heat warnings, the Japan Meteorological Agency is signaling a shift in how the country manages escalating summer temperatures and the associated risks of heatstroke and systemic failure.
