Japan’s Highest Temperatures: New Record of 41.8ºC Set in August 2025

Japan recorded a new highest ever temperature of 41.8° Celsius in Isesaki, Gunma, on August 5, 2025. Before summer 2025, the country’s joint high was 41.1° in Kumagaya, Saitama, in July 2018 and Hamamatsu, Shizuoka, in August 2020.

The first record of the temperature rising above 40° came in July 1927 when the mercury rose to 40.2° in Uwajima, Ehime. In July 1933, it reached 40.8° in Yamagata, Yamagata, which is thought to have been caused by warm, dry foehn winds descending from the mountains. Japan’s top temperature remained unchanged for more than 70 years until August 16, 2007, when it hit a new high of 40.9° in both Tajimi, Gifu, and Kumagaya.

Summer 2025 has been unusually hot in northern Japan, with the temperature regularly rising above 35°; on July 24, it reached 39.0° even on Japan’s northernmost main island, in Kitami, Hokkaidō.

Japan’s Highest Recorded Temperatures

41.8°

• Isesaki, Gunma (August 5, 2025)

41.4°

• Shizuoka, Shizuoka (August 6, 2025)
• Hatoyama, Saitama (August 5, 2025)

41.2°

• Kiryū, Gunma (August 5, 2025)
• Tanba, Hyōgo (July 30, 2025)

41.1°

• Hamamatsu, Shizuoka (August 17, 2020)
• Kumagaya, Saitama (July 23, 2018)

41.0°

• Maebashi, Gunma (August 5, 2025)
• Sano, Tochigi (July 29, 2024)
• Mino, Gifu (August 8, 2018)
• Gero, Gifu (August 6, 2018)
• Shimanto, Kōchi (August 12, 2013)

40.9°

• Hamamatsu, Shizuoka (August 16, 2020)
• Tajimi, Gifu (August 16, 2007)
• Kumagaya, Saitama (August 16, 2007)

40.8°

• Tainai, Niigata (August 23, 2018)
• Ōme, Tokyo (July 23, 2018)
• Tajimi, Gifu (August 17, 2007)
• Yamagata, Yamagata (July 25, 1933)

40.7°

• Kumagaya, Saitama (August 5, 2025)
• Tajimi, Gifu (July 23, 2018)
• Tajimi, Gifu (July 18, 2018)
• Kōfu, Yamanashi (August 10, 2013)
• Shimanto, Kōchi (August 10, 2013)

40.6°

• Koga, Ibaraki (August 5, 2025)
• Fukuchiyama, Kyoto (July 30, 2025)
• Nagaoka, Niigata (August 15, 2019)
• Mino, Gifu (July 18, 2018)
• Kōfu, Yamanashi (August 11, 2013)
• Katsuragi, Wakayama (August 8, 1994)
• Tenryū, Shizuoka (August 4, 1994)

40.5°

• Kiryū, Gunma (August 11, 2020)
• Isesaki, Gunma (August 11, 2020)
• Gero, Gifu (August 8, 2018)
• Kōshū, Yamanashi (August 10, 2013)

Created by Nippon.com based on data from the Japan Meteorological Agency.

Data Sources

• Data on record high temperatures (Japanese) from the Japan Meteorological Agency.

(Translated from Japanese. Banner photo: Getting hydrated outside Kaibara Station in Tanba, Hyōgo Prefecture, where a record high temperature in Japan of 41.2° Celsius was recorded on July 30, 2025. © Jiji.)