Report from the Copernicus observatory indicates that temperatures remain above average; the month was 1.46 ºC above the pre-industrial level
September 2025 was the 3rd hottest in global history, according to a document released this Thursday (Oct 9, 2025) by the European observatory. The result confirms the trend of maintaining the high temperatures observed in previous months.
The global average temperature in September was 16.11 ºC, an increase of 0.66 ºC compared to the average for the same period from 1991 to 2020. According to the report, the temperature was 1.46 ºC above the average estimated for the pre-industrial period, from 1850 to 1900.
The month of September this year was 0.27 ºC cooler compared to that recorded in 2023 and 0.07 ºC in 2024. The report highlights that the small drop does not represent a slowdown in global warming.
“One year later, the global temperature context remains largely the same, with persistently high temperatures on land and sea surfaces reflecting the continued influence of the accumulation of greenhouse gases in the atmosphere,” said Samantha Burgess, ECMWF Climate Strategy Lead (European Centre for Medium-Range Weather Forecasts), in the bulletin.
In the interval from October 2024 to September 2025, the temperature was 1.51 ºC higher than the pre-industrial level (1850 to 1900). The value is still above the 1.5 °C limit established by the Paris Agreement to avoid the worst effects of climate change.
In Europe, the average was 15.95°C, exceeding the average for September from 1991 to 2020 by 1.23°C. This value represents the 5th hottest September ever recorded on the continent.
Temperatures were significantly high in Eastern Europe and Scandinavia. In addition to the European continent, regions of Greenland, northwestern Siberia, adjacent coastal areas and regions of Antarctica recorded temperatures significantly higher than normal.
According to Copernicus, the global average sea surface temperature was 20.72 ºC, which makes September 2025 the 3rd September with the highest ocean temperature ever recorded.
In the Arctic, the average daily ice extent was the 14th lowest ever recorded, around 12% below average, close to the negative record of September 2012. In Antarctica, sea ice reached the 3rd lowest value in history, around 5% below average, behind only 2023 and 2024.
The previous report indicated that in history for the month, with a global average temperature of 16.60 °C, representing an increase of 0.49 °C compared to the average for the period 1991 to 2020.
