Quote:Averaging over 12-month periods smooths out shorter-term variations in regional- and global-average temperatures.
Globally, the annual average for the latest 12-month period (November 2024 to October 2025) was:
0.62°C above the 1991-2020 average, and 1.50°C above the estimated 1850-1900 average used to define the pre-industrial level
0.14°C below the record global-average temperature anomaly of 0.76°C above the 1991-2020 average registered for each of the three 12-month periods ending in June, July and August 2024.
With 10 months of data now available for 2025, it is possible to further refine the temperature outlook for the year as a whole, as well as its expected ranking. Averaged over January to October, the global temperature anomaly currently stands at 0.60°C above the 1991–2020 average, making 2025 the second-warmest year for this 10-month period, 0.12°C cooler than 2024 and 0.04°C warmer than 2023.
Our projection of the global temperature anomaly for the full year, based on a simple statistical model fitted to past ERA5 data, gives a 95% confidence interval of 0.57°C to 0.63°C above average. This would make 2025 the second- or third-warmest year, possibly tied with 2023 (0.60°C), which currently ranks second, and behind 2024 (0.72°C), the warmest year on record. The predicted range corresponds to 1.45–1.51°C above the 1850–1900 pre-industrial reference, with our model indicating less than a 10% chance of exceeding 1.5°C. However, with the global average temperature having reached 1.48°C in 2023 and 1.60°C in 2024 relative to the pre-industrial level, even the lower end of the predicted range for 2025 would result in a 3-year average above 1.5°C, according to the ERA5 dataset*. This would be the first time that this has occurred in the instrumental period.
Even though 2025 may end up as warm as 2023, the climate context of the two years differs. In particular, the recent onset of La Niña conditions is expected to have a moderating effect on global temperature anomalies towards the end of 2025, whereas the end of 2023 was marked by a strong El Niño event reaching its peak intensity, contributing to higher global temperature anomalies.
Looking at the graph we see temperatures steadily and pretty rapidly approaching the first danger point of 1.5°C above “preindustrial” and there is nothing there to slow it when crossing that marker temperature. We can also see that in about 1990 and again in about 2012 the temperature increase accelerated.