September 2025, one of the warmest months on record

September 2025 ranked as the third warmest "ninth month” on record on Earth, according to data published by the Copernicus Climate Change Service. Global average temperatures reached 16.11 °C, 1.47 °C above the pre-industrial average (1850-1900). This extremely high temperature level is part of a global trend of "straining” temperatures, dictated by the continued accumulation of greenhouse gases, starting from human activity. "The global temperature context remains the same, with stubbornly high values over land and at the sea surface,” commented Samantha Burgess, climate strategist at Copernicus.

• Most affected regions: Eastern Europe, polar regions and coasts

Unusually high temperatures were predominantly observed in: Eastern Europe, including the Baltics and the Balkans, parts of Canada, Greenland and northwestern Siberia, coastal regions near the South and North Poles. These areas recorded more pronounced anomalies compared to the average climate values recorded after World War II.

• Heavy precipitation, but also regional drought

In addition to the global heat wave, Copernicus reported large differences in the distribution of precipitation: regions in Europe (Italy, Croatia, the Black Sea coast, Scandinavia) suffered heavy rains, with risks of flooding; in North America, northern India and eastern Russia, September was drier than average, accentuating drought conditions, according to climate.copernicus.eu. Causes of this climate situation: Anthropogenic factor - Emissions of carbon dioxide, methane and other greenhouse gases continue to shake the Earth's thermal balance; Amplifying effects - Polar regions, which are warming faster than the global average, contribute to the decrease in ice surface area and reduced reflectivity, aggravating the phenomenon.

A recent study proposes a new way to quantify extreme heat events, combining frequency, magnitude, duration and affected area. Applied to Europe, the authors reveal an almost tenfold amplification of the intensity of these phenomena compared to the period 1961-1990.

Data so far indicate that 2025 could be the third hottest year globally, after 2024 and 2023, if current trends persist. This succession of records - 2023, 2024, 2025 - suggests a new climate benchmark: what seemed exceptional is becoming increasingly common.