August 2026 ties July 2023 as the warmest month ever measured

The Copernicus Climate Change Service, run by the European Centre for Medium-Range Weather Forecasts, found that August 2026 had a global mean surface air temperature of 16.96°C. That is 0.85°C above the 1991–2020 average for August and warmer than the previous August records, both 16.82°C, set in 2023 and 2024. Across every calendar month in the ERA5 record, which starts in 1940, August 2026 ties July 2023 (16.95°C). The gap is less than a hundredth of a degree.

August ran 0.06°C warmer than July 2026. July is usually the hottest month of the year. ERA5 has only four earlier years in which August beat July: 1945, 1951, 1955 and 1985. Against the 1850–1900 estimate used as a pre-industrial baseline, August 2026 stood 1.65°C higher. It was the first month to clear 1.5°C since November 2025. June to August 2026 matched 2024 as the joint-warmest boreal summer.

Land, sea, and western Europe

The average temperature over global land in August was 15.73°C, a shade above the August 2024 record of 15.71°C. Extra-polar sea surface temperature, between 60°S and 60°N, averaged 21.07°C, the highest August on record and level with March 2024 as the highest month of any name. A daily extra-polar SST of 21.11°C was the highest in the dataset. Copernicus pointed to long-term warming from fossil fuels and to a strengthening El Niño in the equatorial Pacific.

Europe’s land average was 20.26°C, 1.10°C above 1991–2020, the fourth-warmest August for the continent and the warmest summer on record for western Europe. Rivers including the Rhine, Danube, Vistula, Rhône and Po ran exceptionally low. Samantha Burgess, ECMWF’s strategic lead for climate, called August “a remarkable month in the global climate record” — the warmest August and, jointly, the warmest month measured.

A monthly figure above 1.5°C is not the Paris Agreement breach on its own. That threshold is defined as a long-term average. It is still the number governments used as a line. The United Nations said last week that a lasting crossing of 1.5°C is now “unavoidable.” Copernicus does not legislate. It publishes the thermometer. For August the thermometer read 16.96°C, and that is now the shared peak with July 2023.