Colorado recorded its hottest statewide September temperature ever, according to preliminary data from the National Centers for Environmental Information (NCEI).
According to the NCEI (a subset of the National Oceanic and Atmospheric Administration), Colorado recorded an average statewide temperature of 62.9 degrees in September, making it 5.6 degrees above the 125-year average and the warmest on record.
The previous statewide record was a 62.6-degree average statewide temperature, set in 2015.
It’s of relatively little surprise that this record was notched, considering how many statewide cities either set their hottest September on record or came close to doing so. Colorado Springs and Pueblo both set their hottest Septembers on record, and Denver officially recorded its second-hottest, though the Stapleton Airport climate site recorded its warmest September ever.
The warmth mostly owes to a persistent and dominant ridge of high pressure that anchored over the southwestern U.S. throughout most of September. Spurts of unprecedented heat early in the month — including the latest 100-degree day on record in Denver — started Colorado’s September in an exceptionally warm way.
The warm weather, however, also came with extremely dry conditions in September across the state. That has contributed to an expanding drought across Colorado, particularly in the western and southern portions of the state. In southwest Colorado, a paltry monsoon season has contributed to the recent introduction of severe drought to the region, even after a wet and cool winter and spring.
From a wider scale, changes to the climate have potentially suppressed recent September snowfall and expanded summer later and later.
Nationally, it was the second-hottest September on record, only trailing 1998 for the contiguous Lower 48. New Mexico, Texas, Louisiana and Ohio also recorded their warmest statewide Septembers on record, according to the NCEI.
