Scientists say August was Earth's hottest month they've measured

Visitors pass by the cooling fog device at Gwangmyeong Cave tourist site in Gwangmyeong, South Korea, Aug. 6, 2026. Ahn Young-joon/AP hide caption

WASHINGTON — Earth cooked to its hottest month on record in August, blowing far past a key climate threshold, due to the dangerous double whammy of human-caused climate change and a supersized El Nino, according to the European climate service Copernicus.

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August's sizzle also helped push the globe and the United States to swelter through the hottest Northern Hemisphere summer scientists have measured.

Last month the world averaged 62.53 degrees Fahrenheit (16.96 degrees Celsius), which technically was one-hundredth of a degree Celsius more than the all-time global mark set in July 2023, but because that's also the uncertainty level, it's considered a tie, said Samantha Burgess, strategic climate lead for Copernicus.

"It is now time to stop acting surprised that our warming planet keeps getting warmer. This is occurring exactly as forecast by scientists literally decades ago," Texas A&M University climate scientist Andrew Dessler said in an email. "The interesting question is not whether we will keep breaking heat records (we will), but whether we're going to do anything about it or just stand there while the climate train runs us over."

Globally, August was 1.65 degrees Celsius (nearly 3 degrees Fahrenheit) above pre-industrial levels, far exceeding the longer term 1.5 degrees Celsius (2.7 degrees Fahrenheit) threshold set by the 2015 Paris climate agreement. The eight hottest months on record have all been from July 2023 on, according to Copernicus data.

"Our climate system is really operating well outside the range we would have expected just a decade ago," Burgess said Wednesday from a United Kingdom that has been beset with heat waves. "We've transitioned from climate being very abstract and perhaps impacting the global South or far away places to climate impacting and disrupting our daily lives with schools closing, hospitals being overwhelmed, roads melting, train lines buckling. And the reality is we will get more of these conditions that we've seen this summer."

Global monthly ocean temperatures in August tied a March 2024 all-time record for warmest month recorded, while Aug. 22 set a record for hottest day recorded in the world's seas, according to Copernicus.

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An extra hot summer hits

"This summer has really been exceptional. We've seen records that existed for close to 100 years be broken, in the U.S. in particular," Burgess said.

The U.S. National Oceanic and Atmospheric Administration on Wednesday announced that for the first time, summer in the Lower 48 states was hotter than during the peak of the devastating Dust Bowl in 1936. June through August of 2026 in the contiguous United States averaged 74.37 degrees (23.54 degrees Celsius), nearly four tenths of a degree warmer than the mark set 90 years earlier. Globally, this past summer also tied, with 2024, for the hottest on record, according to Copernicus.

In the U.S., August smashed heat records by more than half a degree Fahrenheit, averaging 75.58 degrees (24.21 degrees Celsius) and the average daytime high was a blistering 88.56 degrees (31.42 degrees Celsius), also a record. July was similarly record hot in the U.S., erasing another long-standing Dust Bowl mark.

That records are regularly getting broken, and that August and not July which is traditionally warmer set an all-time record, are signs that human-caused climate change is accelerating, Berkeley Earth climate scientist Zeke Hausfather said.

Copernicus data goes back to 1940. NOAA data for the United States goes back to 1895 and global data, which generally matches Copernicus data but takes longer to calculate, dates back to 1880.

Fossil fuels, El Nino blamed

Several scientists said while El Nino is a factor, this natural and temporary warming of parts of the Pacific that warps and warms weather globally is nowhere as big a cause as the heat-trapping gases emitted as humans burn coal, oil and natural gas.

"While El Nino is starting to ramp up the heat, the underlying driver remains our relentless burning of fossil fuels. Climate change makes every El Nino hotter, and until we stop burning coal, oil, and gas these record-shattering months will simply keep on coming," said Friederike Otto, a climate scientist at Imperial College London.

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Burgess said El Nino generally adds only one or two tenths of a degree Celsius (two to four tenths Fahrenheit) to the global temperature with the overwhelming rest of the heat coming from the burning of fossil fuels.

This El Nino is forecast, however, to break records for strength in the coming months. And as temperatures continue to rise, heat waves, storms, floods and wildfires will get more frequent and more dangerous, said Texas Tech climate scientist Katharine Hayhoe.

According to Hausfather, "it is increasingly likely that 2026 ends up beating 2024 as the warmest year on record, and almost certain that 2027 beats both, potentially reaching as high as 1.8 degrees Celsius (3.2 degrees Fahrenheit) above preindustrial levels on the back of an unprecedentedly-strong El Nino event."

Some days may hit an even higher climate threshold, 2 degrees Celsius (3.6 degrees Fahrenheit) above mid 1800s, Burgess said.

"Until humanity stops burning colossal amount of coal, oil and gas, the pollution this causes will keep baking our planet, and extreme heat will keep smashing all-time records, killing millions and costing trillions, hitting transport and health systems, and pushing up prices for household basics like food," United Nations climate chief Simon Stiell said. "This is the spiraling price of humanity's fossil fuel addiction, and the global climate crisis it is fueling."

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