September 2026 sets new heat record across the contiguous United States
September 2026 was the warmest September on record for the contiguous U.S., with an average temperature of 69.42 °F, far above the 20th-century norm.
According to one outlet Oceanic and Atmospheric Administration, September 2026 set a new temperature high for the contiguous United States, averaging 69.42 °F (20.79 °C). This figure exceeds the typical 20th-century September average by more than 4.5 °F. The month adds to an already extreme year, as the January-through-September span was the warmest nine-month period recorded since at least 1895. Climate scientists such as Zeke Hausfather and Zachary Labe have warned that if the final quarter of the year remains warm, 2026 may surpass the previous record set in 2024. While the exact ranking will depend on October-December temperatures, the unprecedented warmth highlights the broader trend of rising temperatures and associated societal impacts.
Why it matters
The record heat signals accelerating climate change, affecting ecosystems, agriculture, and public health across the United States.
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