Denver came out of the third warmest September on record with precipitation slightly below normal for the month.
September got off to a blazing start with unseasonably hot weather for the first eight days of the month set up by a large upper-level ridge of high pressure that dominated the Western United States, according to the National Weather Service.
The average temperature at Denver International Airport for September was 69.0 degrees, which is 4.2 degrees above normal, the weather service said in a climate summary report for Denver. The monthly mark fell just 0.4 degrees of tying the record.
There were 10 days with maximum temperatures at or above 90 degrees in the city — the most ever recorded in Denver weather history.
“Denver set new record-high temperatures from the 6th through the 8th with temperatures of 98, 99 and 99 degrees, respectively,” the weather service said.
After the early heat wave, a cold front brought much cooler weather to Denver through Sept. 9-10. Denver, for the most part, experienced above-normal temps and mostly dry weather for the final three weeks of the month as upper-level high pressure set up over the region. Occasional upper-level troughs and associated cold fronts resulted in a “few cooler days with below normal temperatures and light precipitation.”
The four warmest Septembers in Denver have come within the past seven years. The warmest September in Denver, based on average temperature, is 2015 at 69.4 degrees, according to the weather service. Second place is 2019 at 69.3 degrees; fourth place is 2021 at 68.8 degrees.
The coldest September, based on the average temperature, in Denver in September was set back in 1912, with 54.7 degrees.
In September 2022, there were no days with temperatures at or below 32 degrees.
Denver received 1.25 inches of precipitation last month, which is 0.10 inches below the normal amount of 1.35 inches, the weather service said. There were six days with measurable precipitation in September, with the highest amount — 0.50 inches — recorded on Sept. 2. No snow fell at DIA, where Denver’s official marks are measured, which is 0.8 inches below normal.
