September 2025 was the third warmest September since records began, according to researchers, with temperatures 1.47°C above pre-industrial levels (1850–1900).
Looking at the period from October 2024 to September 2025, average temperatures were actually 1.51°C above pre-industrial levels, surpassing the critical 1.5°C threshold that the international community aims to avoid to prevent catastrophic climate impacts. Officially, the target is considered exceeded only if this level is surpassed for several consecutive years.
Despite the heat, September 2025 was slightly cooler than record-breaking Septembers in 2023 (0.27°C cooler) and 2024 (0.07°C cooler).
Record temperatures were particularly pronounced in southwestern Europe, including southern France and the Iberian Peninsula. In Spain, more than 1,100 people died due to extreme heat, and thousands were forced to evacuate amid wildfires in Spain and Portugal.
Beyond Europe, unusually high temperatures were observed in Siberia, Antarctica, the Middle East, and parts of Asia, including China, Japan, and the Korean Peninsula.
According to Copernicus, these trends highlight the urgent need to reduce emissions and adapt to increasingly frequent and intense climate extremes.
