Japan is reeling from an unprecedented summer of extreme heat, with temperature records being shattered across the nation and the consequences cascading through public health, agriculture, and the economy. The country logged its highest temperature ever recorded in early august 2025, part of an intensifying pattern that experts attribute to climate change.
On august 5, 2025, the city of Isesaki in Gunma Prefecture recorded a sweltering 41.8°C (107.2°F), setting a new national all-time high. This milestone surpassed a record set just a week earlier, highlighting the rapid escalation of the heat. The Japan Meteorological Agency has confirmed that at least 17 all-time high temperatures have been broken across the country since july.
The heat has been particularly relentless in the nation's capital. As of august 27, Tokyo set a new record with ten consecutive days of temperatures reaching 35°C (95°F) or higher, the longest such streak since observations began in 1875. On the same day, temperatures soared to 39.4°C in Hatoyama Town, Saitama Prefecture, while Kumagaya City marked its 23rd day of the year over 35°C, another local record.
The human cost of the heatwave has been severe. More than 53,000 people have been hospitalized for heatstroke this summer, prompting authorities to issue urgent warnings. Residents have been advised to stay hydrated, limit outdoor activities during peak heat hours, and utilize cooling centers.
The crisis extends beyond public health, deeply affecting Japan's food and water supplies. The country's northeast region, a crucial area for rice farming, is facing severe drought conditions and increased pest activity, threatening this year's harvest. Widespread concerns over low rainfall have led to dried reservoirs, putting immense pressure on water supplies for both agricultural and residential use.
The economic impact is also being felt in the nation's markets and kitchens. Warming sea temperatures have devastated marine ecosystems, leading to a surge in seafood prices. On Rishiri Island in Hokkaido, the local sea urchin catch has been halved as sea temperatures have risen by approximately 5°C in recent years. This has caused the price of a luxury rice bowl with 100 grams of bafun sea urchin to double, now costing between 15,000 and 18,000 yen ($100–$120).
The Japan Meteorological Agency had forecasted an unusually hot summer, citing ongoing global warming and rising sea surface temperatures as the primary drivers. As Japan confronts the tangible consequences of a warming planet, this summer's extreme heat serves as a stark reminder of the escalating challenges ahead.