Overview
- The global daily average sea-surface temperature peaked at 21.1°C on Saturday, 22 August 2026, a new record reported by the EU climate service Copernicus.
- The 21.1°C reading edges past the previous daily high of 21.09°C from March 2024 and follows July 2026 setting a highest-ever monthly average of 20.96°C.
- Copernicus and climate experts attribute the spike primarily to decades of human-caused warming, with a strong developing El Niño adding extra short-term heat to the oceans.
- Warmer seas are already increasing marine heatwave days, which have more than tripled since the early 1990s, and are reducing the ocean’s ability to absorb CO2 while raising the odds of heavier storms and coastal impacts.
- Scientists warn the developing El Niño could push sea-surface temperatures still higher this year, with knock-on effects for fisheries, coral reefs and regional weather patterns such as droughts and floods.