March 2026 was the warmest March on record for the lower 48 US states and the most abnormally hot month of any kind in 132 years of federal records. According to NOAA, the contiguous US averaged 50.85°F, which is 9.4°F above the 20th-century March baseline.
Why it matters
The record is not just about one warm month. The 12-month period from April 2025 to March 2026 is now the warmest ever recorded for the contiguous United States. A forecast El Niño could push temperatures even higher through the rest of 2026.
The numbers
Ten states recorded their warmest March on record: Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oklahoma, Texas, Utah, and Wyoming. Maximum daytime temperatures averaged 11.4°F above the March norm.
According to NOAA data, it was the first time any month’s average temperature exceeded 9°F above the 20th-century baseline. The previous record for most abnormally hot month was January 2006, which ran 8.5°F above its baseline.
El Niño ahead
NOAA predicts a 61% chance that El Niño will develop between May and July 2026. A strong El Niño, combined with the long-term warming trend, could make 2026 or 2027 the hottest year on record globally.
According to Columbia University’s International Research Institute, if El Niño reaches “super” strength, it would compound the extreme heat already observed and increase the likelihood of drought in the US Southwest and flooding in the Southeast.
What the data does not show
The March record reflects weather across the contiguous US only. Global data from the Copernicus Climate Change Service shows March 2026 was the second-warmest globally, behind March 2025.