June 2025, the hottest month in Japan's history: a new signal of the global climate crisis

Japan recorded its hottest June on record, according to the Japan Meteorological Agency (JMA), in a context in which extreme heat waves are becoming more frequent amid accelerating climate change. The monthly average temperature was 2.34°C above the historical average, and the record comes after a succession of atypically hot and dry seasons.

• Historical records and immediate effects

According to the JMA, the hot months of 2024 and 2025 have consistently matched or exceeded records set in more than a century of meteorological observations, which began in Japan in 1898. At the same time, the temperature of the waters around the Japanese archipelago rose by 1.2°C, reaching the same record level as in June 2024 - the warmest since measurements began in 1982.

In addition, meteorologists warn that the heat wave will continue in July, seriously affecting public health, agriculture and ecosystems.

• Alarming manifestations of climate change

Sakura cherry trees began to bloom prematurely or inadequately due to milder autumns and winters, which can no longer trigger the flowering process naturally. Mount Fuji, a national symbol, was deprived of its snow cap until early November, a month later than normal. The rainy season has ended three weeks early in the country's western regions, threatening water supplies and affecting agriculture. Deadly heat waves and increasingly intense and unpredictable summer typhoons are ravaging entire regions, particularly affecting the elderly.

Dry winters are increasing the risk of forest fires, while other parts of the archipelago are experiencing extreme snowfall.

• Long-term consequences

While the JMA warns that not every extreme weather event can be directly linked to climate change, the long-term trend is clear: global warming is increasing the frequency, duration and intensity of extreme weather events. Japan, like many other island or coastal states, is highly vulnerable to such changes. In a global climate where Europe is simultaneously experiencing sweltering heat waves and North America is facing unprecedented wildfires, recent events in Japan are part of a broader picture of the global climate crisis.

In the short term, Japanese authorities are bracing for a scorching summer and a new typhoon season. In the long term, however, drastic measures are needed to mitigate greenhouse gas emissions, adapt infrastructure and protect vulnerable populations.