Temperatures in central Japan exceeded 40°C on Tuesday, marking the first "extreme-heat days" of 2026 [1, 2].
This surge in temperature represents a significant public health risk, prompting authorities to issue heat-stroke alerts across 42 prefectures [5]. The scale of the heat wave is unprecedented for the current year, with a record 276 locations reporting "very-hot days" [4].
In Gifu Prefecture, Tajimi recorded a maximum temperature of 40.3°C [1]. Gujō, also in Gifu, reached 40.0°C [3]. Meanwhile, Toyoda City in Aichi Prefecture hit 40.1°C [2]. Other reports indicate the highest nationwide temperature during this period reached 40.4°C in Kuwana, Mie [8].
Local residents described the conditions as overwhelming. One unnamed resident said the sweating was unbearable and caused dizziness, and noted that the temperature difference between the outdoors and indoors was too extreme to endure [9].
Meteorologists attribute the spike to a strong high-pressure ridge positioned over central Japan [10]. This atmospheric pattern has lifted temperatures to record levels and is expected to maintain the heat through the weekend [2, 3].
Forecasts for Wednesday and Thursday suggest the trend will continue. Nagoya and Kumagaya are both expected to reach maximum temperatures of 40°C on July 22 and 23 [6, 7]. The Japan Meteorological Agency and local authorities continue to urge caution as the "disaster-level" heat persists [1, 2].
“Temperatures topped 40°C in three locations as 42 prefectures issued heat-stroke alerts.”
The emergence of 'disaster-level' heat early in the summer season suggests an intensifying pattern of extreme weather in Japan. With nearly 300 locations hitting 'very-hot' thresholds and multiple cities crossing the 40°C mark, the strain on public health infrastructure and energy grids for cooling is likely to increase as these temperature spikes become more frequent.
