August 2026 is the warmest August Copernicus has recorded

August 2026 was the warmest August in the Copernicus Climate Change Service record. The global surface air temperature averaged 16.96 degrees Celsius, 0.85 degrees above the 1991-2020 August mean. That figure passed the joint August records of 2023 and 2024, both 16.82 degrees. Against a pre-industrial baseline the month sat about 1.65 degrees higher. The reading is statistically level with July 2023, previously the hottest calendar month Copernicus had published.

The ocean did more of the work than the land. Extra-polar sea surface temperature, measured between 60 degrees south and 60 degrees north, averaged 21.07 degrees in August, above the previous August mark of 20.98 degrees set in 2023. Daily extra-polar sea surface temperature has been the highest on record for each calendar day since 19 June. On 24 and 25 August the daily value reached 21.11 degrees, just above the 21.09 degree peak from March 2024. March and April are usually the warmest months for the global ocean. The new high arrived in late summer.

NOAA's National Centers for Environmental Information, using a different baseline, called August the warmest in its 1850-2026 series, 1.32 degrees Celsius above the twentieth-century average and 0.08 degrees above the tied 2023 and 2024 Augusts. June to August was also the warmest such season in that set. The Northern Hemisphere had its warmest summer. Arctic and Antarctic sea ice sat below average. Nineteen tropical storms put global cyclone activity above the mean.

El Nino is the near-term amplifier. Copernicus notes that strong El Nino conditions developed in 2023 and are developing again in 2026. Forecasts it cites say the present event may exceed 2023. If the last four months of 2026 are as warm as the same stretch in 2023, the annual average would approach 2024, the warmest year on file. Samantha Burgess at Copernicus said people have not lived through a summer this warm in the past 100,000 years. That claim rests on paleoclimate reconstructions, not on thermometer records, and should be read that way.

The United Nations said last week that consistently moving past the Paris Agreement's 1.5 degree threshold is now unavoidable. August at 1.65 degrees above pre-industrial does not by itself lock in a multi-year breach. A year that stays this far above the line would. Western Europe has already had its hottest summer on record in the Copernicus series. Temperature departures of 2 degrees or more covered parts of Europe, Africa, Asia, Antarctica and a wide belt of the central and eastern tropical Pacific, the classic El Nino footprint.

What the monthly bulletin cannot do is assign a single storm or fire to the 0.14 degree gap between this August and the last record. What it can do is fix the baseline for the rest of the year. If the equatorial Pacific keeps warming into December, the next four Copernicus releases will be written against a bar that has already moved. Energy and food desks will feel that as harvest risk and as cooling demand before they feel it as a conference text.

Copernicus uses ERA5, a reanalysis that blends observations and a weather model. NOAA uses its own merged land-ocean series. The two offices do not publish identical anomalies. They agree on the ranking: this August sits at the top of the instrumental record. That agreement is the fact that matters for anyone who has to plan a harvest, a cooling load or an insurance book for the last third of 2026.

The practical takeaway from the August file is the ocean record. Air temperature grabs the headline. The extra-polar sea surface, at an all-time daily high in the wrong season, is the reservoir that will keep feeding the atmosphere after the calendar turns.