The Japan Meteorological Agency and regional forecasters expect several cities to record temperatures exceeding 40°C today and through Friday [1, 2].
This extreme heat poses a significant public health risk, as the forecast predicts a surge of "extremely hot days" across the country. The trend is particularly notable in Nagoya, which is expected to record its first day above 40°C this year [2].
Forecasters identified several cities likely to exceed the 40°C mark today, including Nagoya, Kumagaya in Saitama, Tatebayashi in Gunma, Tajimi in Gifu, and Toyota in Aichi [2]. In Tokyo, the predicted maximum temperature is 37°C [2]. Other data suggests between seven and 14 locations nationwide may record temperatures above 40°C in 2026 [3].
Meteorologists attribute the current conditions to a combination of strengthening Pacific and Tibetan anticyclones. These high-pressure systems are compounding with accumulated daily heat, the effects of urbanization, and global warming [1].
"There is no wind, the air is stagnant, and heat is accumulating," a TBS NEWS DIG weather reporter said [1].
A TBS NEWS DIG meteorologist said the dangerous heat is expected to persist because multiple factors are overlapping, including the anticyclones and the long-term impact of climate change [1].
Local authorities are urging residents to take precautions against heatstroke as the stagnant air prevents natural cooling in urban centers. The combination of high humidity and extreme temperatures increases the risk of heat-related illnesses across the affected regions [1, 2].
“Nagoya is expected to record its first day above 40°C this year.”
The convergence of two major anticyclones alongside the "urban heat island" effect demonstrates how local infrastructure and global climate trends amplify extreme weather. When these factors align, temperatures can reach lethal levels quickly, challenging Japan's public health infrastructure and increasing the reliance on energy-intensive cooling systems.
