Summer 2023 Hottest on Record in Japan

Japan experienced its hottest ever summer in 2023. The average temperature for June–August, according to the Japan Meteorological Agency, was the highest on record. Based on measurements at 15 observation stations across the country, it was 1.76°C higher than for a normal year over the last three decades (1991–2020) and the highest since statistics began in 1898. This far exceeded the previous highest average temperature of 1.08°C above normal, recorded in summer 2010.

The rise is due to westerly winds meandering further north than normal, leading to warm air spreading more over northern Japan, while sea surface temperatures around the country climbed to 1.0°C above normal, the highest since records began in 1982. Notably, in August sea surface temperatures exceeded 30°C for the first time in the waters along the coast of the Sea of Japan from Yamagata Prefecture to the Noto Peninsula.

The average temperature by region, based on data from 149 observation stations, was highest since records began in 1956 in Hokkaidō, Tōhoku, Hokuriku, Kantō Kōshin, Tōkai, and Chūgoku. In the Kansai region, the average temperature equaled record highs for 1994 and 2018. Markedly, Hokkaidō was 3.0°C and Tōhoku 2.9°C above normal.

Mean Temperature Deviation by Region

Created by Nippon.com based on data from the Japan Meteorological Agency. Yellow highlighting indicates the top 10% of observation values between 1991 and 2020.

The Japan Meteorological Agency predicts that the warm front will continue from September to November across the whole of Japan, so high temperatures are set to continue.

(Translated from Japanese. Banner photo © Pixta.)