Japan Records Fifth Hottest Summer in 2026

Greater Frequency of Days Over 40°

Data from the Japan Meteorological Agency shows that as of August 31, a cumulative total of 7,528 locations in summer 2026 marked a maximum daily temperature of 35° Celsius or higher at the agency’s observation stations across Japan. (This figure adds together all the locations each day that reach the temperature.) Based on comparable statistics since 2010, this is the third highest number in total, behind 9,385 in 2025 and 8,821 in 2024.

Meanwhile, there was a cumulative total of 36 locations with a maximum temperature of 40° or higher at observation stations. This is the highest number ever recorded since the 2010 rollout of current measurement methods.

The average temperature this summer (June to August) was 1.02° higher than the normal level (based on the 30-year average up to 2020), thus marking the fifth hottest summer since records were first kept in 1898. Hotter summers were recorded in 2025 (2.36° higher), 2023 and 2024 (1.76° higher), and 2010 (1.08° higher).

From August onward, a massive high-pressure system settled over western Japan, bringing a long stretch of hot, dry weather. Meanwhile, the east of the country saw below-average temperatures, especially around Tokyo and the surrounding Kantō area, due to cold air moving down from the north. However, atmospheric conditions turned stormy as eastern Japan became squeezed between a giant low-pressure system to the south and a high-pressure system to the east. This instability caused the severe tropical storm Chan-hom to hit Ibaraki Prefecture and brought torrential rain to neighboring Chiba Prefecture.

Data Sources

• Data on average summer temperature deviations and weather analysis (both in Japanese) from the Japan Meteorological Agency.

(Translated from Japanese. Banner image © PhotoAC.)