"Even Traveling Feels Daunting" 10 Consecutive Days Over 35 Degrees... Japan Endures Severe Heatwave

2.36 Degrees Higher Than Average in Japan
Dual High-Pressure Systems Identified as Cause of Heatwave

Japan is experiencing an unprecedented heatwave. Last month, the daily high temperature in Tokyo exceeded 35 degrees Celsius for ten consecutive days.

According to Nihon Keizai Shimbun (Nikkei), Asahi Shimbun, and other sources, the Japan Meteorological Agency announced on September 1 that the average temperature this summer was the highest ever recorded. The average temperature in Japan from June to August this year was 2.36 degrees Celsius higher than the 30-year average from 1991. This far surpasses the previous record set in 2023, when the temperature was 1.76 degrees Celsius above average.

A pedestrian is walking on a street in Tokyo holding a parasol. Photo by AFP Yonhap News

In particular, Tokyo recorded a total of 26 days this year with temperatures of 35 degrees Celsius or higher, the most in history. In central Tokyo, the daily high exceeded 35 degrees for ten consecutive days from August 18 to 27. There were also several instances of extremely high temperatures. In Isesaki, Gunma Prefecture, in central Honshu, the temperature soared to a record high of 41.8 degrees on August 5.

This record-breaking heatwave is attributed to the simultaneous expansion of the North Pacific High and the Tibetan High, which together blanketed the Japanese archipelago. The Japan Meteorological Agency predicts that warm air will likely continue to cover the country for the next month, resulting in sustained high temperatures for the time being.

This pressure pattern is also affecting the Korean Peninsula in a similar way. The repeated overlap of the North Pacific High and the Tibetan High over the peninsula has led to what is being recorded as the "hottest summer." According to data released by the Korea Meteorological Administration, the average temperature in Korea during the summer of 2025 was 25.7 degrees Celsius, the highest since the expansion of the observation network in 1973. The average daily high was 30.7 degrees, and the average nighttime low was 21.9 degrees, both ranking first on record. The number of tropical nights reached 15.5 days.

The number of heatwave days averaged 28.1, ranking third in history after 2018 and 1994. Summer rainfall was only about 85% of the average, and some regions, such as Yeongdong in Gangwon Province, are experiencing severe drought conditions.