Global daily sea surface temperature breaks record in June 2026, hints at global marine heatwaves

The global average sea surface temperatures (SST) have broken previous records for the month of June in 2026, according to the latest updates from the Copernicus Climate Change Service (C3S) and Copernicus Marine Environment Monitoring Service (CMEMS) on July 1, 2026. The main reason for this surge in temperatures could be the heating from the strengthening El Niño conditions in the Equatorial Pacific Ocean. 

On June 21, daily SSTs from C3S broke the 2023 and 2024 record of 20.83ºC, marginally, at 20.86ºC. On the same day, daily SST data from CMEMS also reached 21ºC, breaking previous records from 2023 and 2024 by 0.1ºC. 

“Over the past three years, the global ocean outside the polar regions (between the 60°N and 60°S latitude) has been between 0.35ºC-0.73º C warmer than the long-term average, and in June these anomalies have now reached record-high levels for the time of year,” according to a press release from C3S. 

“Current conditions could indicate the beginning of a new phase, leading, once more, to uncharted territory. With ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months,” said Carlo Buontempo, director of C3S at the European Centre for Medium-Range Weather Forecasts (ECMWF) in the press release. 

“That Copernicus Marine data reaches the same conclusion through independent methods speaks to the strength of European science — and to why open, robust data matters now more than ever,” said Buontempo. 

“Continuous monitoring of the ocean by CMEMS helps public authorities, scientists and decision‑makers understand how the ocean is changing and supports policies to protect the marine environment,” said Pierre-Yves Le Traon, scientific director of CMEMS, Mercator Ocean International. 

Whether the breaking of the global average daily SST record is temporary or if this is indicative of ocean conditions in the following months is uncertain at this point, according to C3S. The climate context of the previous record in June 2024 and this year is different. “When global SST last reached record levels for this date in June 2024, ENSO conditions were returning to neutral after the El Niño event starting in spring 2023,” said C3S in the press release. 

Warmer than normal oceans would mean warmer atmosphere for longer periods of time. This could lead to availability of extra energy and moisture from evaporation for storm formation, which could in turn lead to extreme precipitation and flooding in different regions around the world. 

“Ocean warming also contributes to sea level rise and ice melt, and stresses marine ecosystems,” as per C3S. The heating of the oceans could is also associated with frequent and intense marine heatwaves. During marine heatwaves, the temperatures of the sea and ocean surfaces increase much above normal, impacting marine ecosystems and fisheries. These events could also affect coastal economies and intensify extreme heat events on land.  

The warming of the oceans was expected by climate scientists at C3S and around the world, with the onset of El Niño conditions, declared by the National Oceanic and Atmospheric Administration of the United States on June 11 and alerted by the World Meteorological Organization on June 2. Record temperatures have also been observed in the northern Pacific Ocean in the last few months. 

“Additionally, an El Niño event is a source of heat for the atmosphere, increasing global temperature and shifting weather patterns across the globe,” as per C3S.

“Copernicus scientists continue to monitor the situation to determine whether the exceedance is temporary or persistent. Nevertheless, with forecasts pointing to a likely strong El Niño, it is anticipated that global temperatures will see new records in the coming months, both in the ocean and in the surface atmosphere,” according to C3S.