September 2026 second warmest on record, global temperatures exceed: C3S

September 2026 was the second warmest September ever recorded globally and marked the second consecutive month in 2026, with global temperatures exceeding 1.5°C above the pre-industrial levels, new data shows.

Global temperatures reached 1.63°C above the pre-industrial level in September, continuing a new run of months above 1.5°C which started in August and is expected to continue into 2027, the Copernicus Climate Change Service (C3S) said on Monday.

C3S data had earlier shown August was the joint warmest month ever recorded globally, tied with July 2023. The global average surface air temperature was 1.65°C higher than the estimated pre-industrial baseline this August, also making it the first month to exceed 1.5°C since November 2025, it said.

Meanwhile the September average sea surface temperature (SST) is the highest on record for the month, amid strengthening El Niño conditions, C3S said, adding El Niño should continue to strengthen in the equatorial Pacific, likely resulting in one of the strongest El Niño events ever recorded.

“The average SST for extra-polar oceans (60°S–60°N) in September 2026 was the highest on record for the month, at 21.05°C, surpassing the previous September record of 20.92°C set in 2023. Meanwhile, around Antarctica, the sea ice extent reached its third-lowest annual winter maximum,” the report said.

Copernicus is the Earth observation component of the European Union’s Space programme. It includes assistance from the European Centre for Medium-Range Weather Forecasts (ECMWF) -- both as a research institute and operational service which gives global numerical weather predictions.

This comes days after the World Meteorological Organization (WMO) on October 8 said El Niño will continue to intensify in the coming months and is likely to see peak levels in December. It is likely to bring above-average temperatures to much of the globe and shift rainfall patterns, increasing the risk of drought and floods in different regions, it had said.

Carlo Buontempo, Director of the Copernicus Climate Change Service said September saw exceptionally high temperatures again across parts of Europe after an extreme summer.

“We are in a new run of months above 1.5°C, and with a strong El Niño still intensifying it is likely to last into 2027. Crossing the Paris Agreement’s long-term limit is only a matter of time. How far we overshoot, and for how long, is still up to us. Copernicus data to guide that choice are free and open to all,” he said.