The European Union's Copernicus Climate Change Service said on Friday that October 2026 was the warmest October ever recorded. Global surface air temperatures were about 1.7C above the pre-industrial average, narrowly beating the previous record set in October 2023. The service attributed the jump largely to a strengthening El Niño in the tropical Pacific.

Copernicus, which is run by the European Centre for Medium-Range Weather Forecasts from Reading and Bonn, publishes its monthly climate bulletin in the first week of each month. Its data draws on billions of measurements from satellites, ships, aircraft and weather stations worldwide. The previous October record, set during the 2023 El Niño, had stood for three years.

The bulletin said sea surface temperatures across much of the equatorial Pacific were well above average. It also reported that Arctic sea ice extent was again among the lowest for the time of year in the satellite record. Scientists at the US National Oceanic and Atmospheric Administration had declared El Niño conditions earlier in the year, and their forecasts show the event persisting through the northern winter.

The deputy director of the Copernicus service said the figures placed 2026 firmly among the warmest years on record. Climate scientists at the UK Met Office have already forecast that 2027, when the full warming effect of El Niño typically arrives, could surpass 2024 as the hottest year measured. Such a result would push the long-term average closer to the 1.5C limit set under the Paris Agreement.

The release came three days before the United Nations COP31 climate conference opens in Antalya, Turkey. Negotiators there are expected to face pressure to strengthen national emissions pledges, which the UN Environment Programme has said remain far short of what is needed. The World Meteorological Organization is due to publish its provisional State of the Global Climate update as the summit begins.