Colorado Air Quality & Wildfire Smoke
Live AQI for 5 Colorado cities, plus statewide air-quality alerts. Data from AirNow (U.S. EPA).
Wildfire smoke in Colorado
Smoke risk across Colorado concentrates in July through September, driven by fires across the northern Rockies and the Great Basin, with terrain that traps smoke overnight and clears it by afternoon.
The 5 cities tracked here span roughly 198 miles, which is far enough that they routinely sit in different air masses. A reading in Denver does not describe the whole state during a plume — check the city nearest you rather than assuming the largest one is representative.
Each city page below shows AirNow's reported AQI on the 2024 EPA breakpoints, with the reporting monitor and the observation time — see how we calculate AQI. Statewide watches and warnings come from the National Weather Service and appear at the top of this page when active.
Cross-border check: the nearest city we track outside Colorado is Cheyenne, WY, about 97 miles north of Denver. Smoke does not stop at state lines — when a plume covers that city's monitors, Colorado's edge nearest it is usually seeing the same air.
Our next-nearest tracked readings sit in Santa Fe, NM (284 mi south) and Albuquerque, NM (333 mi south) — useful second opinions when Colorado's own reading looks odd, and the honest picture of how coarse national smoke coverage is at this resolution.
Colorado is one of the more closely watched states in our national coverage — we track 5 cities here, more than most states — so intra-state differences are visible rather than averaged away.
Readers in Colorado during smoke season: our keep-smoke-out guide and the $70 Corsi-Rosenthal box cover the indoor side; the Can I go outside? tool answers the outdoor question for the current AQI.