Hottest Falls In US History
January through September 2026 was the warmest such period on record for the contiguous U.S., averaging 59.25°F, according to NOAA’s National Centers for Environmental Information. That is 4.18°F above the 20th-century average and 0.42°F above the previous record, set in 2012. Daily temperature records were also set in 200 of America’s largest cities, ranked by the Census Bureau’s Vintage 2025 population estimates. City temperature data came from the Global Historical Climatology Network.
To find the hottest falls on record, we used the National Weather Service’s definition of fall, September 1 to November 30, and calculated the average temperature for those dates in each year. We used the 1901–2000 average of 53.54°F as the benchmark. Our analysis covers only the 48 contiguous states.
Seven of the 10 hottest falls on record have occurred since 2015, consistent with the effects of global warming. 2016 tops the list, followed by 2024 in second place and 2025 in third.
Climate Central analyzed much of the same data and reached a related conclusion: “New Climate Central analysis shows that human-caused climate change is the leading driver of fall warming trends in 82% of 245 major U.S. cities analyzed from 1970-2025.” The cities warming most are Reno, El Paso, Las Vegas, Tyler, and Tucson, all of which are known for 100°F days in summer.
| Rank | Year | Avg temp | Departure |
|---|---|---|---|
| 1 | 2016 | 57.58°F | +4.04°F |
| 2 | 2024 | 57.56°F | +4.02°F |
| 3 | 2025 | 57.20°F | +3.66°F |
| 4 | 2015 | 56.77°F | +3.23°F |
| 5 | 2021 | 56.60°F | +3.06°F |
| 6 | 1963 | 56.57°F | +3.03°F |
| 7 | 1998 | 56.32°F | +2.78°F |
| 8 | 1931 | 56.01°F | +2.47°F |
| 9 | 2023 | 56.00°F | +2.46°F |
| 10 | 2005 | 55.90°F | +2.36°F |
Seven of the 10 come after 2000, and 2016 edged out 2024 by just 0.02°F. The full ranking of all 131 falls is in the attached CSV.
Fall 2026: NOAA hasn’t yet posted a September–October figure, because October data usually comes out in early November. September’s data is already available: it averaged 69.42°F, the warmest September on record. That is 4.58°F above the 20th-century September average and beats the previous record of 68.95°F, set in 1998.
More from ClimateCrisis 247
- The Fish, Birds, and Mussels America Just Lost for Good
- Tornado Season Looks Different Now: Is Your State on the List?
- The Least Reliable Electric Vehicles, According to Consumer Reports
- At the Wall of Wind, engineers blow homes apart to learn how to save them
