Japan recorded its first scorching day of the year on July 18, 2026, with three locations reaching 40°C [1], [3].
This extreme temperature spike signals the arrival of a severe heat wave that could disrupt public health and infrastructure across the archipelago. The frequency of such "scorching days"—defined by temperatures hitting the 40°C mark—has become a critical metric for monitoring climate trends in East Asia.
The Japan Weather Association said the extreme heat is expected to persist, with forecasts predicting another scorching day on July 22 [2], [3]. This trend follows a broader seasonal outlook suggesting that between seven and 14 locations nationwide could reach 40°C or higher during 2026 [2].
Local impacts were felt across various prefectures. In Oita Prefecture, Hita City saw maximum temperatures exceed 35°C [4]. While some reports focused on the widespread nature of the heat, the peak temperatures in three specific areas reached the 40°C threshold [1].
Weather officials said the current conditions are the result of a severe heat wave. The Japan Weather Association continues to monitor the atmospheric patterns driving these unusually high temperatures as the summer progresses [2].
Authorities are urging residents to take precautions against heatstroke as the country prepares for the next projected peak in temperature on Wednesday [3].
“Three locations reached 40°C on the first scorching day.”
The early arrival of 40°C temperatures in July indicates a high-intensity summer for Japan. If the forecast of up to 14 locations hitting this threshold proves accurate, it suggests a significant increase in extreme heat events compared to historical norms, potentially straining the national power grid and increasing heat-related mortality rates.
