The Japan Meteorological Agency (JMA) has declared that the summer of 2025 was the warmest since official temperature records began in 1898. On average, temperatures were a staggering 2.36°C higher than the long-term average, marking an “abnormal heat” this year.
Extreme Heat Across the Country
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June saw a barrage of high temperatures, with 13 scorching days recorded in central Tokyo—more than ever before.
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July brought near-record heat, with some areas like Hokkaido nearing 40°C.
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In August, the situation intensified:
- On August 5, Isesaki in Gunma Prefecture soared to 41.8°C, becoming the highest temperature ever recorded in Japan.
- Even at the end of August (30th and 31st), daily highs again surpassed 40°C, bringing the total number of days over 40°C to nine, another national record.
What It Means
This extraordinary heat wave isn’t just an outlier—it’s a definitive signal of shifting climate norms. Spanning from June through August, the summer of 2025 stands as Japan’s hottest on record, with temperatures far exceeding usual seasonal expectations. The JMA clearly emphasized the gravity of this trend, labeling it “abnormal heat.”
Broader Implications
Such prolonged and intense heat raises serious concerns about the future—including public health risks, energy consumption spikes, and climate adaptation challenges. As Japan—and the world—grapple with more frequent and extreme weather, this season’s record highs highlight the urgent need for climate resilience and mitigation strategies.
