August 2026 ties July 2023 as the hottest month in the ERA5 record

The Copernicus Climate Change Service, run from the European Centre for Medium-Range Weather Forecasts, put August 2026 at 16.96C for global surface air. That is 0.85C above the 1991-2020 average for August and 1.65C above the 1850-1900 baseline. It is the warmest August in the ERA5 record, above the 16.82C shared by August 2023 and August 2024. Across all calendar months it ties July 2023, which stood at 16.95C. The gap is less than 0.01C.

August was also 0.06C warmer than July 2026. In ERA5, which starts in 1940, August has beaten July in the same year only four times before: 1945, 1951, 1955 and 1985. July is usually the peak. This year the peak moved. August was the first month above 1.5C over the pre-industrial baseline since November 2025.

Land ran hot. The global land average for August was 15.73C, a new August record, just above 15.71C in 2024. Extra-polar sea surface temperature, 60S to 60N, averaged 21.07C, the highest August on record and joint highest of any month, level with March 2024. Daily extra-polar SST hit 21.11C on 24 and 25 August.

Europe's August land temperature was 20.26C, 1.10C above 1991-2020, the fourth-warmest August in ERA5 and 0.63C cooler than 2022. France, Italy, the Balkans, Hungary and Romania saw anomalies of 3C to 5C during heatwaves. Northern Europe, from Iceland through Fennoscandia to the Baltics, was nearer average or slightly below. The June-August season over Europe was the third-warmest in the dataset. Western Europe had its warmest summer on record at 21.69C, 2.54C above 1991-2020, above 2003. National services in France, the United Kingdom, Ireland, the Netherlands, Belgium, Spain and Austria reported the same pattern.

NOAA, using a different baseline, also called August the warmest in its 1850-2026 series, 1.32C above the twentieth-century average, and said all ten of the warmest Augusts have arrived since 2016. The lower 48 US states averaged 75.6F, 3.5F above the twentieth-century August mean, a national record for the month.

The Pacific is the near-term driver on top of the long rise from fossil fuel use. Copernicus and the World Meteorological Organization describe a rapidly developing El Nino in the equatorial Pacific, with the Nino 3.4 region already in El Nino and a chance the event becomes stronger than 2023 as it runs into 2027. That extra surface warmth in the tropical Pacific tends to lift global averages in the months after it peaks.

The 1.5C line in the Paris Agreement is a long-term average, not a single month. A month above that line does not by itself mean the goal is gone. It does mean the instrument record is now producing individual months that sit in the zone governments once treated as a ceiling. Copernicus will publish September next month. If El Nino keeps rising, the next few monthly bullets will be read against this August number, not against 2023.