Boulder County, Colorado
AQI 50 · Good50
Median AQI
76
90th Percentile
119
Max AQI
273
Days with Data
Ranked #21 of 27 counties in Colorado (by median AQI, lower is better)
Monthly Median AQI — 2025
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50
Median AQI
76
90th Percentile
119
Max AQI
273
Days with Data
Ranked #21 of 27 counties in Colorado (by median AQI, lower is better)
Click a bar to view that month's details