This September was the hottest ever on record for the U.S.

October 8, 20262 min read Add Us On GoogleAdd SciAmIt’s been a blistering year. A record-hot September doesn’t bode well for the rest of it chuchart duangdaw/Getty ImagesJoin Our Community of Science Lovers!September 2026 shattered the record for the hottest September ever recorded in the contiguous U.S., according to new data from the National Oceanic and Atmospheric Administration. It marks another sobering record for an already historically hot year.This past January through September were the hottest first nine months of any year in the U.S. since at least 1895.Overall, the contiguous U.S. averaged a balmy 69.42 degrees Fahrenheit (20.79 degrees Celsius) in September—more than 4.5 degrees F (about 2.5 degrees C) higher than the historical 20th-century average.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.Whether 2026 will break the record for the U.S.’s hottest year—currently standing at 55.48 degrees F (about 13 degrees C), set in 2024—depends on the temperatures for October, November and December. As Scientific American previously reported, climate predictions are complicated. But what is clear is that such a warm September only makes the situation more dire.Leading up to now, the period of the first eight months of the year, January–August, was exceptionally hot. If the period of September–December averages around 50.5 degrees F (10.3 degrees C)—a warm but not unusual scenario for recent years—the U.S. is likely to break its record, climatologist Zeke Hausfather previously told Scientific American.Crowning 2026 as the hottest year would only be part of the picture; climate change doesn’t care about records.As Climate Central scientist Zachary Labe previously told Scientific American, “Whether 2026 ultimately ranks as number one or number three doesn’t distract from the bigger story that temperatures are rising across the country and leading to major impacts for communities.”Editor’s Note (10/8/26): This is a breaking news story and may be updated.Subscribe to Support Independent JournalismGreat science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber