The Copernicus Climate Change Service (C3S) reports that September 2025 was the third-warmest September ever recorded globally, with an average ERA5 surface air temperature of 16.11 °C – 0.66 °C above the 1991–2020 average for the month. This follows September 2023, the warmest on record, and September 2024, only slightly warmer by 0.07 °C.
Across Europe, the average land temperature reached 15.95 °C, ranking as the fifth warmest September on record and sitting 1.23 °C above the 1991–2020 average. The image, based on C3S data, shows surface air temperature anomalies across parts of the northern hemisphere, Africa, and Asia.
At sea, the average global sea surface temperature (SST) for September 2025 over 60°S–60°N was 20.72 °C, the third-highest value on record for the month and 0.20 °C below the September 2023 record. In the Arctic, the daily sea ice extent reached its 14th-lowest annual minimum in the satellite record, while the monthly extent ranked 13th lowest – 12% below average but well above the record low of –32% observed in September 2012. Below-average sea ice concentrations were most pronounced north of Svalbard and Franz Josef Land and in the Beaufort Sea.
Precipitation patterns varied across Europe. Northwestern and central regions, Fennoscandia, the eastern Black Sea coast, and parts of Italy, Croatia, and eastern Spain were wetter than average, with heavy rainfall in some areas causing flooding and disruptions. Meanwhile, much of the Iberian Peninsula, the Norwegian coast, peninsular Italy, the Balkans, and parts of Ukraine and western Russia experienced drier-than-average conditions.
Featured image credit: European Union, Copernicus Climate Change Service Data
