September was the world's second warmest on record
Copernicus records exceptionally high temperatures and low river flows in parts of Europe.
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September 2026 was the world's second warmest September since records began. According to Copernicus, the average surface temperature was 1.63 degrees above the estimated pre-industrial level.
The European climate service Copernicus published its monthly measurement for September on Monday. The average global surface temperature was 16.27 degrees Celsius. That was 0.82 degrees above the 1991–2020 average and 0.11 degrees lower than the September record set in 2023.
The month was therefore the second consecutive month in 2026 in which the average global temperature was more than 1.5 degrees above the estimated level for 1850 to 1900. This is a monthly measurement and does not establish that the long-term target of the climate agreement has definitively been exceeded. Longer periods are used for that assessment.
The sea also remained exceptionally warm. According to Copernicus, the average sea-surface temperature between 60 degrees south and 60 degrees north was the highest recorded for a September. A record value was measured in the Niño 3.4 region of the tropical Pacific, while El Niño continued to gain strength, according to the service.
Europe as a whole experienced its third warmest September on record. Western Europe equalled the record set in September 2023. Across large parts of western, central and eastern Europe, the heat coincided with dry conditions. Copernicus reports that parts of the Rhine, Danube and Wisła, as well as the Garonne and Dordogne basins, had exceptionally low river flows.
Low river levels can affect shipping, water supplies and agriculture. The measurement does not say that every individual extreme weather event was directly caused by climate change. However, the temperature series and persistent warmth show what conditions are like now; the development of El Niño and its effects are also incorporated into climate models and forecasts.
A second analysis by Climate Central and a separate overview by the US climate service NOAA also ranked September second. The datasets use different reference periods and methods, but point in the same direction. Copernicus stresses that the data are intended to support policy choices; the measurement itself is not a policy decision.
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The figures and rankings match the primary Copernicus publication and independent climate databases. The text avoids incorrectly equating a monthly value above 1.5 degrees with the long-term target set out in Paris.
- confirmed September 2026 was the world's second warmest September. — Reported by Copernicus, NOAA and Climate Central. source
- confirmed The average global temperature was 16.27 degrees Celsius and 0.82 degrees above 1991–2020. — Copernicus explicitly cites both figures. source
- confirmed September was 1.63 degrees above the estimated pre-industrial level. — Mentioned in Copernicus's temperature highlights. source
- confirmed Parts of European rivers had exceptionally low September flows. — Copernicus mentions the Rhine, Danube, Wisła and Garonne–Dordogne, among others. source
Editor's note
The temperature figures are measurements from Copernicus, NOAA and Climate Central. The text distinguishes monthly values from the long-term climate target and presents El Niño as both a measured and modelled development.Sources
- Copernicus: Second warmest September as global temperatures stay above 1.5°C — Copernicus Climate Change Service
- Monitoring Global Temperature and Precipitation in September 2026 — NOAA National Centers for Environmental Information
- Climate Central’s Monthly Briefing Highlights from September 2026 — Climate Central
More on this in Dutch media
- de Volkskrant — „klimaat temperatuur”
- NU.nl — „klimaat temperatuur”
- De Telegraaf — „klimaat temperatuur”