Global sea surface temperatures have reached a new record high, surpassing the previous mark set in March 2024. On August 22, the daily global average sea surface temperature, excluding polar regions, reached 21.1° Celsius (69.98° Fahrenheit).
According to data from the European Union’s Copernicus Climate Change Service (C3S), the global ocean heat content also set a new record in 2025. These rising temperatures contribute to sea-level rise, intensify marine heatwaves, stress ecosystems like coral reefs, and threaten fisheries and food security. Furthermore, increased sea surface temperatures can heighten the potential for extreme weather events and diminish the ocean’s capacity as a carbon sink.
Source: Mongabay