Copernicus says the findings reflect the “accelerating pace of climate change”.
October 2025 was the third-warmest globally on record, according to data from the EU’s Copernicus Climate Change Service (C3S).
The month recorded an average surface air temperature of 15.14°C, 0.70°C above the 1991-2020 average for October, according to the ERA5 dataset, which uses billions of measurements from satellites, ships, aircraft and weather stations around the world.
C3S now says 2025 is virtually certain to finish as the second- or third-warmest year on record, possibly tied with 2023, the current second-warmest year, and behind 2024, the warmest year on record.
Copernicus says the findings reflect the “accelerating pace of climate change”, which increases global temperatures as the burning of fossil fuels releases greenhouse gases that trap heat in the atmosphere. Global warming is also reducing low-level cloud cover, which causes temperatures to rise.
‘We are now in the decade where the 1.5°C limit is likely to be exceeded’
October 2025 was just 0.16°C cooler than the warmest October on record, in 2023, and 0.11°C cooler than October 2024.
The month was 1.55°C above the estimated 1850-1900 average used to define the pre-industrial level. This makes it the first month above 1.50°C since April 2025.
While 2025 may not reach 1.5°C above the pre-industrial level, average global temperature for 2023–2025 is likely to exceed 1.5°C. According to Copernicus, this would make it the first three-year average to do so since weather records began, a time frame known as the ‘instrumental period’ beginning in the 18th century when climate information began to be collected using scientific instruments.
“We are now in the decade where the 1.5°C limit is likely to be exceeded, highlighting the accelerating pace of climate change and the urgent need for action,” says Samantha Burgess, Strategic Lead for Climate at Copernicus.
Fennoscandia had the highest above-average air temperatures in Europe
The average temperature over European land for October 2025 was 10.19°C, 0.60°C above the 1991-2020 average for October, ranking outside the ten warmest on record.
The most pronounced above-average air temperatures for Europe were recorded over Fennoscandia and the southern Iberian Peninsula.
Below-average temperatures were mainly experienced over southeastern Europe.
Outside Europe, temperatures were most above average over the polar regions, in particular over northeastern Canada, the central Arctic Ocean and East Antarctica.
A large region with pronounced negative temperature anomalies covered much of southern and eastern Russia and Mongolia, as well as the eastern parts of Kazakhstan and northernmost China.
Europe experienced record-breaking sea surface temperatures
The average sea surface temperature (SST) for October 2025, excluding the polar regions, was 20.54°C, the third-highest value on record for the month.
Most of the North Pacific continued to experience significant above-average SSTs, with record highs in the west. In contrast, SSTs were close to or below the 1991-2020 average in the central and eastern equatorial Pacific, reflecting a transition towards weak La Niña conditions.
The European sector of the Arctic Ocean saw much-above to record-breaking SSTs, as did the eastern Indian Ocean, off the coast of Indonesia.
Antarctic sea ice third lowest for October
In the Arctic, the average sea ice extent in October was 12 per cent below average, ranking eighth lowest for the month.
Regionally, sea ice concentrations were most below average in the Eurasian sector of the Arctic Ocean, particularly north of Franz Josef Land and Severnaya Zemlya, coinciding with much-above-average surface air temperatures.
In the Antarctic region, the monthly sea ice extent was the third lowest for October, at 6 per cent below average.
Sea ice concentrations around Antarctica were most below average in the Bellingshausen Sea and in the Indian Ocean sector, the latter coinciding with much-above-average surface air temperatures in the adjacent part of East Antarctica.