Colorado just experienced its hottest summer on record, continuing a months-long streak of above-average temperatures that climate scientists say is made more likely by fossil fuel pollution.
Every one of the past 15 months have been warmer than the 1991-2020 average, according to the Colorado Climate Center. Colorado’s record warm summer has been driven by heat through the western two-thirds of the state, where nearly everywhere experienced its hottest June through August.
“One of the things that struck me the most about this summer is the consistency of the heat,” Colorado State Assistant Climatologist Peter Goble said. “In the typical summer in Colorado, during July or August, you tend to see a couple weeks where we get a cold front. … But we saw almost none of that this summer.”
At one weather station in Dillon, only seven of 92 days throughout the summer were cooler than the average over the past three decades, Goble said. Even on those seven cooler days temperatures were “not that much cooler” than the historical average, he added.
On June 30, for example, temperatures were five degrees below the historical average, while some of the hottest days this summer, such as July 27 and Aug. 22, temperatures soared 11 degrees above average, according to the Climate Center.
Colorado recorded its three hottest August days on record in 2026 — with six of the 10 warmest August days ever recorded in the state in at least the last 100 years occurring this past summer, Goble said. During July, Colorado saw heatwave after heatwave, defined as a four-day period of above-average temperatures, as mountain towns smashed heat records. June kicked off the summer with above-average temperatures and below average precipitation.
Heading into summer, Colorado was already experiencing widespread and severe drought as a result of the record-low snowpack last winter. While precipitation in August was closer to normal, total rainfall through the three summer months trended below-average throughout the state’s mountains, Goble said. He noted that the heat only worsened drought conditions.
Rivers and reservoirs across Colorado have experienced record-low levels this summer, impacting water supplies and industries from recreation to agriculture. The heat and drought also led to extreme fire danger across the mountains through the summer and helped fuel erratic wildfire behavior during major fires, like the Aspen Acres Fire that destroyed more than 300 homes, the Gold Mountain Fire outside of Ouray and the Willow Fire near Leadville.
“We had a very active fire year in Colorado, and that was driven by both the dry conditions over the winter and the low snowpack as well as the heat this summer, giving us more fire weather and more opportunities for wildfire conditions,” Goble said. “With a dry winter followed by a hot summer, you also end up with dry soils and over the long run that does impact the health of our forests.”
This water year, a period that runs from October 1 to Sept. 31 to better track seasonal water cycles, is also certain to go down as the hottest on record — and by a “wide margin,” Goble said.
The current water year is tracking almost 2 degrees warmer than any previous water year, according to the Climate Center. While Goble said that may not seem like a lot for any given day’s weather, it is “huge” when averaged out across an entire year.
June to August was also the warmest on record for the continental U.S. and tied for the warmest globally, according to the National Oceanic and Atmospheric Administration. Climate scientists say this long-term trend of global warming is driven by the burning of fossil fuels, which release heat trapping gasses into the atmosphere.
“When you average across the entire U.S. or especially the globe, it becomes impossible to hide that trend in day-to-day weather variation,” Goble said. “So, certainly we know that our average temperatures are increasing and not every summer is going to be a record warm summer in Colorado, but it becomes more and more probable every year.”
As skiers hype the growing Super El Nino, Goble said there’s no guarantee that the pattern characterized by warming sea temperatures in the Pacific Ocean and a shift in the jet stream will result in more snow for Colorado.
Still, long-term models show above-average chances of precipitation for much of the state through December, offering some hope of relief.
“A lot of people are getting excited about this big El Nino event. A lot of people tend to associate El Nino with more precipitation and more snow in Colorado,” Goble said. “There is evidence that in Colorado, most of the state tends to be wetter during El Nino, especially during the shoulder seasons, both fall and spring. But when it comes to the relationship between El Nino versus La Nina and peak snowpack in the Rockies, there’s just not a strong, statistically significant relationship.”
