Late July heat wave was Colorado’s hottest 4-day period on record
A record-breaking stretch of high temperatures late last month was Colorado’s worst heat wave in the 75 years that such records have been collected, state climatologists said Tuesday.
The four-day period from July 25 to 28 included the first- and third-hottest days in Colorado’s recorded history, as measured by the statewide average temperature. The statewide average of 78.75 degrees Fahrenheit on July 27 exceeded the previous daily record, set in 2005, by more than 1.5 degrees.
That one-day average included a high of 113 degrees Fahrenheit in the Eastern Plains town of Burlington, just two degrees shy of the state’s all-time record high, according to the monthly summary released by Colorado State University’s Colorado Climate Center.
Overall, it was Colorado’s second-hottest July in 132 years of record-keeping, exceeded only by July 2003 — though significant portions of the state, including the Denver metro area and northwest Colorado, recorded their hottest July ever. Nationally, it was the contiguous United States’ single hottest July on record, the National Oceanic and Atmospheric Administration said this week.
More frequent, more intense heat waves are the most direct and unambiguous result of human-caused climate change to be felt in Colorado, the Climate Center concluded in a comprehensive 2024 report, which said with “very high” confidence that the trend is attributable to a changing climate. Impacts like worsening droughts and wildfires were also judged to be attributable to global warming with “high” confidence, relative to more uncertain impacts like higher-frequency severe weather and hail.
Colorado's historic winter warmth last year also shattered previous temperature records, continuing a pattern of extreme conditions across all seasons.
Rising levels of greenhouse gases in the Earth’s atmosphere, mostly the result of burning oil, gas and coal, caused average global temperatures to rise by more than 2.3 degrees Fahrenheit over pre-industrial levels as of 2024, according to NOAA data. Parts of Colorado, including much of the Western Slope, are among the areas in the U.S. where average temperature increases have been most severe — a trend that has accelerated during the 2020s.
Colorado was one of nine states in the West to have experienced its warmest winter on record in 2025-26, and the record-breaking heat has persisted throughout the “water year,” a period beginning in October, as statewide snowpack sank to the lowest level in decades.
© iStock - Xurzon
“Water year 2026 continues to be the warmest on record by a large margin,” Tuesday’s report said. “Statewide average temperature has been 6.2 degrees Fahrenheit higher than the 20th-century average, 4.6 degrees above the 1991–2020 average, and 1.7 degrees warmer than any previous October through July period.”
Researchers have also concluded with increasing confidence that a warming climate is driving the Colorado River Basin’s post-2000 megadrought, through both reduced precipitation and higher rates of evaporation of moisture from water surfaces and soils. These drought conditions, the worst dry spell the region has experienced in at least 1,200 years, are being influenced by human activity “more intensely — and more directly — than previously understood,” researchers at the University of Colorado Boulder warned last year.
As of August 4, 78% of Colorado was classified as experiencing at least “severe” drought conditions, with nearly half the state, including much of the Colorado River Basin on the Western Slope, experiencing “extreme” drought, according to the U.S. Drought Monitor. Precipitation last month was roughly average for July, the Climate Center said.
“The North American Monsoon finally set in during July, but as is often the case, rainfall was spotty,” said the report, with northwest Colorado and the Denver metro area missing out on most of the rainfall.
The National Weather Service’s Climate Prediction Center continues to predict a wetter-than-normal monsoon season for western Colorado, offering hope that relief from extreme drought conditions could be in sight. The arrival of a strong El Niño pattern this summer could also mean higher-than-average precipitation in the fall and winter — though the state Climate Center cautions that “with El Niño in Colorado, it’s important to keep in mind that nothing is guaranteed.”
