Rahul Somvanshi
On August 22, 2026, global ocean temperatures reached 21.10°C, surpassing the previous record of 21.09°C set in March 2024. The milestone marks the highest daily global average sea surface temperature recorded in the ERA5 dataset, which extends back to 1979.
The Copernicus Climate Change Service measures daily global mean sea surface temperature across the 60°S to 60°N band, excluding polar regions. The 21.10°C figure is the absolute daily average temperature recorded for that region. The anomaly or departure from historical baseline averages is approximately 0.67°C to 0.95°C above normal, and this departure is significant.
NOAA reported that July 2026 global ocean temperature was the highest on record for July at 1.84°F (1.02°C) above average. Scientists have linked the record to a strengthening El Niño and long-term warming trends. NOAA’s Climate Prediction Center said that El Niño was strengthening, with a greater than 90% chance of a very strong event during Northern Hemisphere fall and winter 2026–27. El Niño’s strain on the Panama Canal
West Coast waters are experiencing a large marine heatwave, running roughly 3 to 4°F above normal, according to NOAA Fisheries. Ocean heat content continues to build as the world ocean absorbs more than 90% of excess heat from greenhouse gas warming, with cascading effects rippling across fisheries, coastal weather patterns, and marine ecosystems.
Warmer surface layers can reduce vertical mixing in some regions, preventing nutrient cycling that supports lower food web levels. Tropical coral reefs are experiencing persistent thermal stress, with bleaching events recurring as heat conditions persist. The top-ranking monthly global ocean temperature departures have occurred during El Niño episodes, establishing a clear correlation between ENSO events and ocean extremes. a super El Niño since 1950
The August 2026 record comes as scientists continue monitoring ocean absorption rates and regional heatwave intensities. Marine heatwaves now affect approximately 42% of global ocean surface area, according to satellite and in-situ measurement networks. These conditions are expected to persist as El Niño strengthens through the Northern Hemisphere fall and winter, with potential impacts on hurricane season intensity, regional precipitation patterns, and long-term ecosystem health. record European heatwaves
