Thursday’s temperatures included the hottest low in 144 years.
I know that sounds odd, but it’s significant.
According to 9News senior meteorologist Chris Bianchi, Thursday's low of 74 degrees was the second warmest low temperature ever recorded in Denver. And the last time Denver experienced a low that hot was on July 3, 1881.
“If you drop down only to 74 degrees, that means the majority of the nighttime hours it's above 80,” Bianchi said. “That is a really difficult thing to overcome in terms of cooling off at night. And that's something we're just not accustomed to.”
According to Weather Underground, the 74-degree mark was recorded at 4:53 a.m., much deeper in the night — or morning — than you’d expect. Denver’s summertime lows average in the 50 to 60 degree range.
Bianchi notes that the way we measure temperature has changed significantly since the 1880s. Back then, they measured on a rooftop downtown. Today, it’s taken at Denver International Airport. Meaning, Denver’s low was likely even hotter.
“In downtown Denver, we most likely drop down overnight to about 77 or 80 degrees, depending on exactly where we are,” Bianchi said. “So, if the record that we just set had been taken in downtown Denver, where the 1881 measurement was, it likely would've been somewhere between 77 and 80 degrees.”
The U.S. Army Signal Corps began taking official weather observations in 1872 from a three-story brick building down the street from the Broadwell House. Denver would move its official weather collection site to the Stapleton Airport in 1950 and, finally, to Denver International Airport when it opened in 1995, due to the Federal Aviation Administration’s requirement of accurate weather observations for airline safety.
Denver also tied its second-hottest day on record based on average temperature. Thursday's average temp was 86.5 degrees. That record has been set three other times since 1881. The highest average temperature recorded was 88 degrees on June 26, 2012.
