August 2026 Tied as Warmest Month on Record as U.S. Logs Hottest Meteorological Summer

August 2026 was the joint warmest month in the global instrumental record, according to the European Union’s Copernicus Climate Change Service, while the contiguous United States just had its warmest meteorological summer on record, according to the National Oceanic and Atmospheric Administration, reinforcing a common message from major climate agencies: long-term human-caused warming, amplified this year by an exceptionally strong El Niño, is pushing heat to extraordinary levels on land and at sea.

In a Sept. 10 update, Copernicus said the global average surface-air temperature in August was 16.96 degrees Celsius, or 0.85 degrees C above the 1991-2020 average and 1.65 degrees C above the 1850-1900 preindustrial baseline. It said August 2026 was the first month above 1.5 degrees C over that preindustrial benchmark since November 2025. Copernicus described August 2026 as the “joint warmest” month in its ERA5 dataset, tied with July 2023, because any tiny numerical difference between the two falls within the dataset’s uncertainty.

“August 2026 was a remarkable month in the global climate record. It was both the warmest August and the warmest month ever recorded, with global temperatures reaching 1.65°C above pre‑industrial levels, marking the return of global temperatures above 1.5°C,” Samantha Burgess of Copernicus and the European Centre for Medium-Range Weather Forecasts said in the release.

NOAA’s National Centers for Environmental Information, in a Sept. 9 summary, said the contiguous U.S. averaged 75.6 degrees Fahrenheit in August, 3.5 degrees F above the 20th-century average and the warmest August in the 132-year record for the lower 48 states. For meteorological summer, the June-through-August period used by forecasters and climate agencies, the contiguous U.S. averaged 74.4 degrees F, or 3.0 degrees F above average, making it the warmest summer in that 132-year record. NOAA said that exceeded previous records, including 1936 and 2021, by about 0.4 degrees F.

The broad drivers are familiar, but this year they are reinforcing each other: the long-term warming caused by greenhouse gas emissions and a powerful El Niño, the natural Pacific climate pattern that can temporarily raise global temperatures. The World Meteorological Organization said Sept. 3 that forecasts showed an “exceptionally high likelihood of nearly 100%” that El Niño would persist through February 2027, and warned it could be stronger than any seen since monitoring began.

The heat is also showing up in the oceans. Copernicus said the average sea-surface temperature for the extra-polar ocean — meaning waters between 60 degrees south and 60 degrees north — was 21.07 degrees C, the highest on record for August. It also reported the highest daily extra-polar sea-surface temperature ever recorded, 21.11 degrees C on Aug. 22. On land, NOAA said drought covered about 59.1% of the contiguous U.S. as of Sept. 1, up by more than 10 percentage points since early August, amid mixed precipitation patterns and elevated wildfire potential in parts of the West and Plains. Copernicus also said Western Europe had its warmest summer on record.

One note of caution on the 1.5-degree threshold: a single month above that level does not mean the world has permanently crossed the Paris climate agreement’s most ambitious temperature target. That benchmark refers to a long-term global average, not one month. And while climate agencies sometimes use slightly different wording — such as “joint warmest,” “warmest August” or “warmest month” — because they rely on different datasets, baselines and methods, the overall finding is the same: August 2026 was at or near the top of the record across major monitoring systems, and the long-term warming trend is unmistakable.