On December 9, 2025, the Copernicus Climate Change Service (C3S), implemented by the European Centre for Medium-Range Weather Forecasts, reported that 2025 was on course to be one of the three warmest years on record. Its November bulletin gave the numbers behind that statement. This article summarizes them and puts them in context with the 2026 data that followed.
How warm was November 2025?
The global surface air temperature for November 2025 was 14.02 degrees Celsius, which is 0.65 degrees above the 1991 to 2020 November average and 1.54 degrees above the 1850 to 1900 pre-industrial level. That made it the third-warmest November on record, 0.20 degrees cooler than November 2023 and 0.08 degrees cooler than November 2024. It was the second month after October 2025 above 1.5 degrees since April 2025. The global boreal autumn, from September to November, was the third highest on record, at 0.67 degrees above average.
Where does 2025 rank for the year?
From January to November 2025, the average temperature was 0.60 degrees above the 1991 to 2020 average, or 1.48 degrees above pre-industrial. Those values match the full-year figures for 2023. C3S said 2025 is currently tied with 2023 as the second-warmest year and is virtually certain to finish second or third, with 2024 the warmest year on record. Our report on the record heat of 2026 covers the year that followed.
What about the 1.5 degree level?
C3S said 2025 may not reach 1.5 degrees above pre-industrial for the full year. It added that the 2023 to 2025 three-year average is likely to exceed 1.5 degrees, which would be the first three-year average to do so in the instrumental record, according to ERA5. A three-year average is closer to the idea of long-term warming than a single month, though it is still short. The Paris Agreement’s goal is usually discussed in terms of longer averages, a general point that the bulletin does not argue itself.
What were the oceans doing?
The average sea surface temperature for 60 degrees south to 60 degrees north in November 2025 was 20.42 degrees Celsius, the fourth highest for the month and 0.29 degrees below the November 2023 record. Record highs occurred in the western North Pacific, while cooler conditions in the central and eastern equatorial Pacific accompanied a weak La Niña that was developing. That contrasts with the strong El Niño of late 2026 described in our article on El Niño 2026, a reminder that the ocean pattern shifts the year’s temperature.
How much sea ice was there?
- Arctic: 12 percent below average, the second-lowest for November
- Antarctic: 7 percent below average, the fourth-lowest for November
For the long-term Arctic picture, see our article on the Arctic Report Card 2025.
What about Europe?
European land temperature in November 2025 averaged 5.74 degrees Celsius, 1.38 degrees above the 1991 to 2020 average and the fifth-warmest November. Europe’s autumn was the fourth warmest, at 1.06 degrees above average. November was wetter than average across the UK, Ireland, Iberia and the Balkans, and drier than average in Iceland, northern Italy, central Germany and Sweden.
Why does the three-year average matter?
Single months swing with weather and ocean patterns, so scientists often smooth the record. A three-year average dampens one unusual month but is still shorter than the 20 or 30 year periods used to define climate. Our own reading is that the C3S statement is a signal worth noting without being a verdict on the Paris Agreement goal. The bulletin itself reports the statement without drawing that policy conclusion, and it does not say whether the average will stay above the level.
What do the reference periods mean?
C3S reports anomalies against two baselines. The 1991 to 2020 average is a recent climatology used for comparison with what people have experienced. The 1850 to 1900 level is the pre-industrial reference used for climate targets. A given month can look small against the first and large against the second, which is why the same November appears as 0.65 degrees above average and 1.54 degrees above pre-industrial. The numbers are consistent and measure different things.
How do these numbers connect to the climate system?
Rising temperatures follow the build-up of heat-trapping gases, a process described in our explainers on the greenhouse effect and climate change. Our report on CO2 emissions covers the emissions side. The C3S bulletin reports observations and does not discuss causes, so these links are our own explanatory context.
Glossary: terms used here
- Anomaly: the difference between a measurement and a reference average
- ERA5: the global reanalysis dataset C3S uses for temperature and sea surface temperature figures
- Boreal autumn: September to November in the Northern Hemisphere
- La Niña: the cool phase of the Pacific climate pattern that includes El Niño
- Instrumental record: the period for which direct thermometer-based measurements exist
These definitions are general ones and are not quoted from the C3S bulletin.
How to read the ranking
A ranking such as second or third warmest depends on small differences, and C3S expressed it as virtually certain second or third, not as one fixed place. Our own reading is that the point is not which year wins but that the last three years are far above all earlier ones. The bulletin supports that reading with the three-year average above 1.5 degrees.
Key figures at a glance
- November 2025: 1.54 degrees Celsius above pre-industrial, third-warmest November
- January to November 2025: 1.48 degrees Celsius above pre-industrial
- 2025 ranking: tied with 2023 for second, virtually certain to finish second or third
- Three-year average, 2023 to 2025: likely above 1.5 degrees
- Sea surface temperature, November: 20.42 degrees Celsius, fourth highest
Frequently asked questions
Was 2025 the second-warmest year?
C3S said it was tied with 2023 for second as of December 9, 2025 and virtually certain to finish second or third.
Did 2025 exceed 1.5 degrees?
C3S said the year may not reach 1.5 degrees, but the three-year average for 2023 to 2025 is likely to exceed it.
Which year was warmest?
2024 is the warmest year on record in the C3S bulletin.