April 2026 recorded the second highest sea surface temperatures on record for the extra-polar oceans, with record high temperatures across large parts of the tropical Pacific associated with strong marine heatwaves, as El Niño conditions are expected to develop in the coming months.
It was also the third warmest April on record globally, according to the Copernicus Climate Change Service (C3S), implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF).
Temperature anomalies
April saw significant differences in temperature anomalies across the Northern Hemisphere, although they were less marked than earlier this year.
There were strong regional differences across Europe. Much of southwestern Europe was much warmer than average, with Spain having its warmest April on record. In contrast, Eastern Europe was colder than average.
Thus, April 2026 was the 10th warmest such month on record for the continent, although this ranking conceals regional differences.
Sea ice extent in the Arctic was second lowest for April, staying near record lows for the time of year, as it has been since the beginning of the year, the report said.
Atmospheric instability
The month was also marked by extreme weather events, including tropical cyclones in the Pacific, floods in West Asia and south-central Asia, and droughts affecting southern Africa.
Flash flooding swept across large swathes of the Arabian Peninsula, and parts of Iran, Afghanistan, Saudi Arabia and Syria saw widespread flooding and landslides.
Samantha Burgess, Strategic Lead for Climate at ECMWF, commented: “April 2026 adds to the clear signal of sustained global warmth. Sea surface temperatures (SSTs) were near record levels with widespread marine heatwaves; Arctic sea ice remained well below average, and Europe saw sharp contrasts in temperature and rainfall – all hallmarks of a climate increasingly shaped by extremes.”
Rising heat
The ERA5 dataset indicated that April 2026 was one of the three warmest Aprils on record globally, with an average surface air temperature of 14.89°C, 0.52°C warmer than the average for April during 1991–2020.
April 2024 was the warmest April on record, and April 2025 was the second warmest.
Warming waters
In April, the daily average SST in the extra-polar global ocean (60°S–60°N) was incrementally approaching the record values of 2024, showing the shift from ENSO-neutral towards El Niño conditions, which are now expected in the next few months.
The average sea surface temperature (SST) for April 2026 was the second warmest on record for the month, at 21.00°C, across 60°S–60°N. The last El Niño event was in 2024, when the April SST was the highest on record.
SSTs were at record levels for the month over a large area from the central equatorial Pacific to the western coast of the US and Mexico, consistent with ‘strong’ marine heatwave conditions, according to the Copernicus report.
Published on May 8, 2026