Average global temperatures last month were 0.49°C above the 1991–2020 norm, slightly cooler than August 2023 and 2024 — the two hottest Augusts ever observed. Compared with pre-industrial levels, August 2025 was 1.29°C warmer. Over the past year, from September 2024 to August 2025, global temperatures averaged 0.64°C above the 1991–2020 baseline and 1.53°C higher than pre-industrial levels.
This summer as a whole also ranks as the planet's third hottest, running 0.47°C warmer than average — surpassed only by the record-breaking summers of 2023 and 2024.
Heatwave and wildfire devastation
At 19.46°C, Europe's average temperature for August was 0.3°C above normal, keeping it just outside the continent's top ten warmest Augusts. Yet some regions were hit especially hard: the Iberian Peninsula and southwest France endured scorching heat, with conditions sparking widespread fires.
"In southwest Europe, the month brought the third major heatwave of the summer, accompanied by exceptional wildfires," said Samantha Burgess, Strategic Lead for Climate at the European Centre for Medium-Range Weather Forecasts (ECMWF).
Across the continent, more than one million hectares have burned so far this year — an area larger than Cyprus. Spain alone has lost nearly 400,000 hectares since January, while Portugal has seen over 260,000 hectares consumed by flames, according to Copernicus's European Forest Fire Information System (EFFIS).
A rapid analysis by World Weather Attribution concluded that climate change made the hot, dry and windy conditions behind these fires significantly more likely and more severe.
Overall, Europe recorded its fourth-warmest summer on record, running 0.9°C above average. Much of the continent faced above-normal temperatures, with eastern Europe one of the few exceptions. Western and southern regions, the Balkans, the Black Sea, Scandinavia, Finland and northwestern Russia also experienced unusually dry conditions.
Oceans remain abnormally warm
Globally, sea surface temperatures averaged 20.82°C in August — the third highest value ever registered. Much of the North Pacific was far warmer than normal, with record-breaking heat in several areas.
While Mediterranean waters were less extreme than in 2024, the North Atlantic to the west of France and the UK recorded new highs.
"With the world's oceans also remaining exceptionally warm, these events highlight not only the urgency of cutting emissions but also the critical need to prepare for more frequent and more intense climate extremes," Burgess added.