St. Clair County, Michigan
AQI 39 · Good39
Median AQI
67
90th Percentile
147
Max AQI
303
Days with Data
Ranked #16 of 27 counties in Michigan (by median AQI, lower is better)
Monthly Median AQI — 2025
Click a bar to view that month's details
39
Median AQI
67
90th Percentile
147
Max AQI
303
Days with Data
Ranked #16 of 27 counties in Michigan (by median AQI, lower is better)
Click a bar to view that month's details