tree dayEnvironment news · Development: 9 Oct 2026
Copernicus reports second-warmest September and record September ocean warmth
Copernicus records the second-warmest September globally and a September sea-surface temperature record across 60°S–60°N. Europe also experienced continued warmth and low river flows.
Global / Europe
September 2026 was the second-warmest September globally in the ERA5 record, the Copernicus Climate Change Service reported in a release dated 9 October. Average sea-surface temperature across 60°S–60°N reached a September record of 21.05°C. The service also documented unusually warm, dry conditions across much of Europe. [1]
A monthly reading above 1.5°C
Global surface air temperature was 1.63°C above the estimated 1850–1900 average. A single month above that level differs from an assessment of the Paris Agreement’s long-term warming threshold. The ocean figure also covers a defined latitude band, rather than every part of the sea. [1]
NASA explains that climate is assessed through patterns over time, while weather describes shorter-term conditions. [2] Monthly records are valuable observations within that longer view. Keeping the time period and geographic domain attached to each figure prevents an air-temperature anomaly and an ocean-temperature record from being treated as interchangeable measures.
Low rivers connect heat with daily life
Copernicus reported exceptionally low September flows in parts of the Rhine, Danube, Vistula and Garonne-Dordogne, with disruption to navigation, water supply and agriculture in several countries. [1]
That regional detail gives the global temperature story a practical dimension. River conditions influence how communities and businesses experience a dry period. Later rainfall can bring relief to some locations while creating different problems elsewhere, so following a basin’s conditions remains necessary even within a broadly warm month.
Follow the evidence
Primary reporting and background sources. Event dates and publication dates are shown separately above.
- Copernicus Climate Change Service: Copernicus: Second warmest September as global temperatures stay above 1.5°C ↗
- NASA: What is climate change? ↗
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