August Sets Global Heat Record as Hottest Northern Summer Confirmed
Earth recorded its hottest August on record and its hottest Northern Hemisphere summer, with human-caused warming and a strengthening El Nino driving the extremes.
Earth experienced its warmest August on record last month, edging past the previous global high set in July 2023, according to the European climate service Copernicus. The month averaged 16.96 degrees Celsius (62.53 degrees Fahrenheit), a figure that technically exceeded the July 2023 mark by one-hundredth of a degree Celsius but is treated as a tie because the difference falls within the margin of uncertainty.
August's heat also helped push the globe and the United States through the hottest Northern Hemisphere summer that scientists have measured. Globally, the June-to-August period tied with 2024 as the warmest summer on record, Copernicus said.
The month was 1.65 degrees Celsius (nearly 3 degrees Fahrenheit) above pre-industrial levels, well beyond the 1.5 degrees Celsius threshold set by the 2015 Paris climate agreement. The eight hottest months on record have all occurred from July 2023 onward, according to Copernicus data, which extends back to 1940.
Oceans also felt the strain. Global monthly sea surface temperatures in August matched a March 2024 record for the warmest month recorded, while Aug. 22 set a record for the hottest day measured in the world's seas.
In the United States, the National Oceanic and Atmospheric Administration reported that summer in the Lower 48 states was hotter than during the peak of the Dust Bowl in 1936 for the first time. The contiguous United States averaged 23.54 degrees Celsius (74.37 degrees Fahrenheit) from June through August, nearly four-tenths of a degree warmer than the mark set 90 years earlier. August itself broke US heat records by more than half a degree Fahrenheit, averaging 24.21 degrees Celsius (75.58 degrees Fahrenheit), with an average daytime high of 31.42 degrees Celsius (88.56 degrees Fahrenheit), also a record. July had similarly erased a long-standing Dust Bowl mark.
Scientists attributed the bulk of the warming to heat-trapping gases released by burning coal, oil and natural gas, with El Nino — a natural and temporary warming of parts of the Pacific that distorts weather worldwide — playing a smaller role. Copernicus strategic climate lead Samantha Burgess said El Nino generally adds only one or two tenths of a degree Celsius to the global temperature, with the overwhelming remainder coming from fossil fuel combustion.
"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. "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."
Burgess said the climate system is operating well outside the range expected a decade ago, with effects shifting from distant or abstract concerns to disruptions of daily life — school closures, overwhelmed hospitals, melting roads and buckling train lines. "The reality is we will get more of these conditions that we've seen this summer," she said.
Imperial College London climate scientist Friederike Otto said climate change makes every El Nino hotter, and that record-shattering months will continue until coal, oil and gas use ends. Texas Tech climate scientist Katharine Hayhoe warned that heat waves, storms, floods and wildfires will grow more frequent and more dangerous as temperatures rise.
Berkeley Earth climate scientist Zeke Hausfather said the regularity of broken records, and the fact that August rather than the traditionally warmer July set an all-time high, point to accelerating human-caused climate change. He added that 2026 is increasingly likely to surpass 2024 as the warmest year on record, and that 2027 will almost certainly beat both, potentially reaching 1.8 degrees Celsius (3.2 degrees Fahrenheit) above pre-industrial levels amid an exceptionally strong El Nino. Burgess said some days could exceed a 2 degrees Celsius (3.6 degrees Fahrenheit) threshold above the mid-1800s.
United Nations climate chief Simon Stiell said the pollution from burning fossil fuels will keep driving extreme heat that kills millions and costs trillions, straining transport and health systems and raising prices for household basics such as food.