Contiguous US Breaks Its Record For Hottest Month Ever, NOAA Says

The contiguous United States sizzled to its hottest month ever last month, according to the National Oceanic and Atmospheric Administration. July averaged 76.89 degrees Fahrenheit (24.94 degrees Celsius) across the Lower 48 states, eclipsing the Dust Bowl’s July 1936 by an eighth of a degree. Records go back to 1895. […] Although it was unusually cool in Alaska, hotter-than-normal conditions blanketed the Lower 48, with the most excessive heat in the Mountain West, Southwest, Northern Plains and Southeast. The heat was so widespread that every one of the Lower 48 states was at least 1 degree Fahrenheit (nearly 0.6 degrees Celsius) warmer than the 20th century average, said Russ Vose, chief of monitoring at NOAA’s National Center for Environmental Information.

[…] The biggest driver of the record heat was nighttime lows that smashed the old mark for hottest minimums by 0.7 degrees, NOAA said. Hotter nights are a classic sign of human-caused climate change, according to scientists and several studies in peer-reviewed literature. NOAA’s calculation is based on averaging 24 hours of temperature, not just highs or lows. “If you’re talking heat waves, that nighttime low is incredibly important for determining total heat stress,” [said meteorologist Jeff Masters of Yale Climate Connections]. “So if it doesn’t cool off at night, your body doesn’t have time to readjust to all the heat.” As nighttime temperatures increase, more people die and lose sleep, studies show.

The years 2021 and 1936 tie for America’s hottest summer, which is June through August. Through July, 2026 is a shade cooler than 2021, which was powered by record heat in June. Because of climate change, Masters said, “this may be one of the coolest years we’re gonna experience for the rest of our lives.” What’s needed, Masters said, is “to stop burning so many fossil fuels. We also need to be spending money to adapt to the new climate that we’ve put in place.”