Global sea surface temperatures climbed to their highest level for this time of year in June, surpassing the previous record set in 2024, according to data released by the Copernicus Climate Change Service (C3S) and the Copernicus Marine Service (CMEMS).

According to C3S, the global average sea surface temperature reached 20.86°C in mid-June, which was just slightly above the previous June record of 20.83°C. Using a different dataset, CMEMS found a global average sea surface temperature of 21.0°C, which was about 0.1°C above previous highs.

This record has been set just after the World Meteorological Organization (WMO) confirmed the appearance of El Niño, which is a naturally occurring climate pattern that usually warms the Earth's climate. Given the already existing warm ocean waters, it may result in the creation of more records in the coming months.

Temperatures in oceans outside the Polar Regions have been above the average values for the last three years. The greatest deviations occurred in June 2026, being the largest ever seen in this period of time.

Warming oceans have an impact on the climate that goes well beyond the ocean itself, as the warming waters contribute to a higher exchange of heat and moisture into the atmosphere, and consequently a higher chance of rain, storms, and floods. Warming oceans also lead to increased melting of glaciers and ice sheets, thereby contributing to increased sea levels.

There are other impacts on marine ecosystems, which are affected by warming, including impacts on marine food chains and changes to fish populations.

According to Carlo Buontempo, Director of the Copernicus Climate Change Service at the European Centre for Medium-Range Weather Forecasts, the new data indicates the presence of yet another period of unusually warm oceans. The consistency of two independently developed data sets adds credibility to the findings.

According to Pierre-Yves Le Traon, Scientific Director of the Copernicus Marine Service, constant monitoring makes it possible for governments and researchers to analyze the impacts of changes in the oceans on weather and climate and marine ecosystems.

The latest figures extend a run of unusually high ocean temperatures that has persisted since 2023. Researchers will now be watching how sea surface temperatures evolve through the second half of the year as El Niño develops and its effects become more pronounced.