As last week ended, the world’s oceans smashed a record from 2024 – the hottest daily global average sea surface temperature. It was just shy of 70 degrees Fahrenheit (69.98 degrees, compared to 69.96 in March 2024), according to the Copernicus Climate Change Service (C3S).
C3S is the European Union’s Earth Observation Program. It said the new record temperature was recorded on Aug. 22, marking its highest reading going back to 1979 when the data set was established.
“While daily records should always be interpreted within a broader climate context, this milestone is consistent with the continued long-term warming of the global ocean and the emergence of an extreme El Niño event in the tropical Pacific,” C3S explained.
As of this month the National Weather Service’s Climate Prediction Center in the U.S. said that El Niño conditions were strengthening, “with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.”
El Niño refers to times when the Pacific Ocean warms for several consecutive months, impacting an east-west air flow pattern called the Walker Circulation, shifting it east toward South America. It can impact everything from marine life to prices at the grocery store.
According to C3S, “the timing of the record is particularly notable,” because ocean temperatures usually peak annually in March and April, around the time the last record high was reported. Previously, the highest August temperature was recorded in 2023 (69.764 degrees).
“This latest daily record follows a succession of monthly sea surface temperature records and near-records observed throughout 2026 across the extra-polar ocean (60°S to 60°N), underscoring the persistent warmth seen across much of the global ocean,” C3S noted. This warmth can be at least partially attributed to human-driven climate change, it said.
With that strong El Niño brewing in the Pacific, there’s even more warmth infused into the ocean waters now. In addition to the NWS predictions, the World Meteorological Organization and C3S seasonal forecast a particularly strong El Niño.
Since ocean temperatures can have such a wide-ranging effect, C3S stressed that this new record is about more than just feeling warmer water during an ocean dip.
“The long-term rise in ocean temperatures has far reaching consequences for both communities and ecosystems. A warmer ocean contributes to sea-level rise through thermal expansion, increasing risks for coastal communities and low-lying island nations,” C3S said. “Higher temperatures also increase the likelihood and intensity of marine heatwaves, which can damage key ecosystems, such as coral reefs and seagrass meadows, which in turn disrupt marine food webs and industries such as fisheries and aquaculture.”
Furthermore, the balmy ocean waters can contribute to extreme weather events since more heat and moisture are transferred into the atmosphere. That means rainfall can be more intense, among other changes.
