The contiguous United States logged its warmest September on record, surpassing the previous mark set in 1998, according to a monthly report from the National Oceanic and Atmospheric Administration summarized this week. It is the fourth month this year — after March, July and August — to rank as the warmest in NOAA's 132-year instrumental record, and it extends a streak of above-average monthly temperatures across the Lower 48 to 20 consecutive months, dating back to February 2025.
Forty-three states recorded above-average September temperatures, and eight — Arkansas, Illinois, Kansas, Louisiana, Missouri, New Mexico, Oklahoma and Texas — had their warmest September on record, ABC News reported, citing the NOAA data. Oregon was the only state with below-average temperatures. NOAA attributed the record primarily to unusually warm overnight lows rather than extreme daytime highs; the agency estimated that roughly 80 million people experienced their warmest September nights on record.
A wetter Southwest, a drier South
Precipitation diverged sharply by region. Arizona had its wettest September since 1983 and New Mexico its wettest since 1941, with the Southwest overall receiving more than double its average September rainfall. Hawaii logged 10.83 inches of rain — 6.42 inches above normal — partly due to Hurricane Lowell. Despite that, roughly 55% of the contiguous U.S. remained in drought as of the October 8 U.S. Drought Monitor, with conditions worsening across the southern Plains and the Lower Mississippi and Tennessee valleys even as they improved in parts of the Southwest and northern Plains.
Independent coverage reached similar conclusions using preliminary data. Fox Weather had flagged the month as a likely record in progress, noting it followed the warmest meteorological summer on record for the Lower 48, which NOAA had already announced in September. The full global figures for September, which would allow comparison against the record-warm September of 2023, had not yet been finalized in the sources reviewed for this article; NOAA's National Centers for Environmental Information publishes that analysis separately on its monthly climate report page.
One caveat worth flagging: a single month's ranking, however record-setting, describes weather variability layered on top of a warming trend — it is not, by itself, evidence of any single cause for a given month's heat. Scientists generally attribute the broader multi-decade warming trend behind the pattern to accumulating greenhouse gas emissions, a conclusion based on separate, long-running climate research rather than this monthly report alone.
NOAA is expected to release its final global September assessment and begin October's monitoring data in the coming weeks, which will show whether the above-average streak extends to 21 months.
