October 2025 ranked as the third-warmest October ever recorded, continuing a run of exceptional global warmth that has marked recent years. According to the ERA5 dataset from the Copernicus Climate Change Service (C3S), the average surface air temperature reached 15.14 °C – 0.70 °C above the 1991–2020 average for the month.
October 2025 was 0.16 °C cooler than the warmest October on record, in 2023, and 0.11 °C cooler than October 2024. Compared with the pre-industrial average for 1850–1900, this month was 1.55 °C warmer, marking the first time since April 2025 that the monthly global temperature rose above the 1.5 °C threshold. Over the 12 months from November 2024 to October 2025, the global average was 0.62 °C above the 1991–2020 reference period and 1.50 °C above pre-industrial levels.
This data visualisation, created using C3S data, shows surface air temperature anomalies across part of the Northern Hemisphere during October 2025. The map reveals widespread warmth, particularly across Europe and the Arctic. Europe’s average temperature was 10.19 °C – 0.60 °C above the monthly norm – though the continent did not rank among the ten warmest Octobers on record. The most significant temperature anomalies were observed in Fennoscandia and the southern Iberian Peninsula, while southeastern Europe experienced slightly below-average conditions.
Beyond Europe, strong positive anomalies were recorded in the polar regions, especially over northeastern Canada, the central Arctic Ocean, and East Antarctica. In contrast, a large area of below-average temperatures stretched across southern and eastern Russia, Mongolia, eastern Kazakhstan, and northernmost China.
Sea surface temperatures (SSTs) also remained exceptionally high. The global average SST over 60° S–60° N was 20.54 °C – the third-highest on record for October, 0.24 °C below the 2023 record. Much of the North Pacific registered above-average SSTs, with record values in the western region. The central and eastern equatorial Pacific, however, cooled toward weak La Niña conditions. Meanwhile, the European sector of the Arctic Ocean and the eastern Indian Ocean, near Indonesia, recorded much-above-average to record-breaking SSTs.
According to C3S, 2025 is almost certain to finish as the second- or third-warmest year on record – potentially tied with 2023 and just behind 2024, the warmest year to date. The agency notes that while 2025 may not exceed 1.5 °C above the pre-industrial level, the 2023–2025 global temperature average is likely to surpass that mark for the first time in the instrumental record.
More information is available at the Copernicus Climate Change Service.
Featured image credit: European Union, Copernicus Climate Change Service Data
