Both the contiguous United States and the world’s oceans experienced their hottest July on record, driven by rising carbon emissions and a strengthening El Niño. According to the National Oceanic and Atmospheric Administration (NOAA), temperatures averaged 76.9 degrees Fahrenheit (24.9 degrees Celsius) across the U.S., marking the highest average July temperature in a 132-year record. This figure sits 3.3 degrees Fahrenheit (1.8 degrees Celsius) above the 20th-century average.
Record-Breaking July Heat Surges Across the United States
The extreme heat fueled national headlines with drought conditions, heat domes, and wildfires. NOAA reported that wildfires in eastern Oregon burned over 140,000 acres, multiple Mid-Atlantic cities recorded their warmest July 4 ever, and the Southwest experienced extreme overnight temperatures. According to NOAA, record-breaking nighttime lows acted as the primary driver of the historic July heat, which research identifies as a classic indicator of climate change and a significant public health threat.
Nationwide, nearly 30,000 firefighters battled 98 large, uncontained blazes, with approximately half of those fires burning in the Northwest, according to the National Interagency Fire Center. Meanwhile, drought conditions are projected to persist and expand across parts of the Northwest and east of the Rocky Mountains, including sections of the Great Plains and Upper Midwest.
Global Sea Surface Temperatures Reach New Highs
Global ocean temperatures also reached unprecedented levels. Data from Copernicus, the Earth observation component of the European Union’s space program, showed that average sea surface temperatures across oceans outside the polar regions reached 69.73 degrees Fahrenheit (20.96 degrees Celsius) in July. This figure surpassed the previous July record of 69.6 degrees Fahrenheit (20.89 degrees Celsius) set in 2023.
Scientists warn that the world’s oceans are on the brink of an all-time heat record. Average sea surface temperatures are currently hovering just a few hundredths of a degree below the record set in March 2024. Because temperatures generally continue to rise for months following the emergence of an El Niño, experts note that this record will almost certainly be broken.
Much of the anomalous warmth stems from a tropical Pacific warm band marking the El Niño climate pattern, which forecasts suggest could become the strongest on record. Wide areas of the northern Pacific and Atlantic, alongside much of the Mediterranean Sea, are also notably hotter than average temperatures from the three decades preceding 2020.
Ecosystem Risks and Future Climate Implications
The mounting heat poses severe risks to marine life and coastal regions. Researchers highlight threats to fisheries, such as steep declines in anchovy populations off South America’s Pacific coast, alongside marine heatwaves that elevate humidity and overnight temperatures for coastal populations. Coral reefs face particularly acute vulnerabilities.
In Europe, persistent high-pressure systems trapped heat, amplifying widespread drought and drier-than-average soil conditions that drove extreme wildfires. Experts emphasize that as soils dry out, they lose natural cooling capabilities, allowing heat to accumulate more rapidly.
While the effects of El Niño remain temporary, the impacts of rising carbon emissions do not. Without significant and internationally coordinated intervention, meteorologists caution that current extreme temperatures may represent some of the coolest conditions experienced for decades to come.
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