Japan is preparing for extreme heat and intense thunderstorms across the Kyushu, Tokai, and Kanto regions this Sunday.
The forecast signals a significant public health risk as temperatures climb to levels that can cause heatstroke and disrupt infrastructure. The combination of searing heat and sudden, violent storms creates volatile conditions for millions of residents and travelers.
More than 300 locations are expected to record temperatures above 35°C [2], marking the highest forecast for the year. In some areas, the heat will be even more extreme, with Hita in Ōita, Kuwana in Mie, and Tajimi in Gifu forecast to reach approximately 40-41°C [2].
Major cities are also bracing for high temperatures. Nagoya is forecast to reach 39°C [2], while Osaka is expected to hit 38°C [2]. Tokyo's 23 wards are forecast to reach 35°C [2].
While the heat dominates the forecast, the Kanto region faces additional threats. Very intense thunderstorms are expected in Tokyo's 23 wards on Sunday afternoon [1]. These storms are characterized by their sudden onset and high intensity.
The heatwave is expected to persist into early next week. Forecasters said that Kumamoto may record a temperature of 40°C on Monday [2]. If this occurs, it would be the first time in the city's statistical history that such a temperature has been reached [2].
“More than 300 locations are expected to record temperatures above 35°C”
The potential for Kumamoto to hit 40°C for the first time in recorded history underscores a shifting climatic baseline in Japan. When combined with the forecast of over 300 locations exceeding 35°C, this event demonstrates an increasing frequency of 'extreme heat days' that challenge urban cooling infrastructure and increase the risk of heat-related mortality across multiple prefectures.
