Colorado weather: First sustained heat wave of the summer sweeping through state this week

Boulder Flatirons Diagonal Traffic
Hart Van Denburg/CPR News
Traffic heads towards the Flatirons and Boulder on the Diagonal Highway, June 15, 2023.

Hot, dry summer weather has returned to Colorado and appears here to stay. 

A heatwave bringing 90 to 100-degree temperatures will begin sweeping through the state Monday. The heat is expected to persist through the remainder of the week, and could extend into next week as well. 

National Weather Service meteorologist Frank Cooper said those conditions mean afternoon thunderstorms will likely be less frequent. 

“We're not expecting much, at least through the middle of the week,” he said. “[But] it looks like by maybe Friday into Saturday, we might see at least a slight chance of thunderstorms back into the area.”

Along the I-25 corridor, temperatures in Denver, Fort Collins and Colorado Springs are forecast to reach the upper 80s to mid-90s this week. Pueblo will see the region’s highest temperatures, with highs forecasted in the lower 100s. 

Cooper said even with the heatwave coming, he doesn’t expect the NWS will need to issue a red flag warning for critical fire conditions. 

We've had a lot of water, which means we've got a lot of green,” he said. “The main thing is if it starts to dry out over a prolonged period of time, that could start to be an issue.”

The Western Slope, which has received less rain than the Front Range this summer, will also see temperatures reach into the 100s. While a red flag warning hasn’t been issued for the region, conditions are dryer and more likely to cause critical fire weather. 

Officials are telling people to remain indoors if possible and to stay hydrated if they brave the outdoor heat. Coloradans should look out for symptoms of heat-related illnesses, like heat stroke. People 65 and older, children younger than 2, and people with chronic diseases are most at risk of heat-related illness. 

Air quality will reach moderate levels of unhealthiness in the Denver metro area, Fort Collins and Greeley on Monday, according to the Colorado Department of Public Health and Environment.