Colorado’s monsoon season is over. Summer rains were ‘hit and miss,’ and a warm, dry fall could be ahead

Veronica Penney/CPR News

Colorado had a “hit and miss” monsoon season despite summer rainstorms that brought periods of intense rainfall and flash flooding to parts of the state, said Zach Hiris, a meteorologist with the National Weather Service’s Boulder office.

Much of southern Colorado and the Front Range recorded bursts of heavy rainfall in recent months. Still, the rains recorded during June through August — the period that typically marks the monsoon “season” — were much more mixed in other parts of the state, Hiris said.

Pockets of below-normal seasonal precipitation were recorded near Grand Junction and the Utah border, as well as areas near Glenwood Springs and Pueblo, data from the National Oceanic and Atmospheric Administration that compares precipitation patterns to normal averages recorded from 1991-2020 show.

The data show that the summer monsoon moisture also largely evaded the entire northeastern corner of Colorado, where some of the state’s worst drought conditions are concentrated. Despite frequent deluges in the southern part of the state, Colorado Springs, Pueblo and other cities along the southern Interstate 25 corridor have received slightly below-average precipitation so far this year. 

The timing and amount of monsoon rainfall are crucial to the overall health of the water system in Colorado and other western states. Monsoon rains have become less reliable and less effective due to climate change and its effects on snowpack, soil moisture and other elements of the water cycle.

Hiris said Colorado’s monsoon rains dampened the most dangerous wildfire conditions through the summer months, but seasonal climate models from the National Weather Service’s Climate Prediction Center suggest the state is in for a drier, warmer September, October and November. But he stressed that those models have a lot more uncertainty than short-term forecasts.

“When we get into those fall seasons, it really just takes one or two good storms to either put us above normal or keep us below normal for the season,” he said.