Japan is experiencing a severe heatwave with temperatures in some regions exceeding 38°C [1].

This extreme weather poses a significant public health risk, as temperatures have surpassed typical human body temperature, increasing the likelihood of heat-stroke across multiple prefectures.

Forecasts for Aug. 26, 2026, predict temperatures approaching 40°C [1]. The heat is widespread, affecting residents in Kumamoto, Fukushima, Tochigi, Nagoya, and central Tokyo [1, 2, 3]. In Kumamoto, recorded temperatures have already climbed above 38°C [1].

Earlier this month, the heat began intensifying. Tokyo recorded temperatures above 35°C on Aug. 20, 2026 [4]. In Nagoya and Ts, temperatures had already reached 35°C by the morning of Aug. 26 [5]. Some reports indicated a possibility that Nagoya could experience consecutive days with temperatures of 40°C or higher between Aug. 21 and Aug. 24 [6].

Local residents have described the current conditions as abnormal. "It is a bit abnormal," said a resident in their 70s [1]. The resident said, "It is higher than body temperature, isn't it?" [1].

The current climate event is part of a broader trend of rising temperatures across the country. This year, 40 locations were recorded as "extreme heat days," marking the highest number on record [7].

Meteorologists attribute the surge to a persistent high-pressure system sitting over Japan [8]. This system is trapping heat and preventing cooler air from circulating, leading to the "body-temperature-exceeding" conditions reported in several cities [8].

While some forecasts predicted 40°C or higher for the Tokai region on Aug. 26, some local observations indicated that the peak did not reach that specific threshold in all areas [9, 10]. Despite these slight variations in peak readings, the risk of heat-related illness remains critical across the archipelago.

“"It is a bit abnormal," said a resident in their 70s.”

The increasing frequency of 'extreme heat days' in Japan suggests a shift in seasonal norms, where temperatures consistently exceeding human body temperature are becoming more common. This trend places immense pressure on the national healthcare system and urban infrastructure, particularly in densely populated cities like Tokyo and Nagoya, requiring more aggressive public health interventions to prevent mass heat-stroke casualties.