Winnebago County, Illinois
AQI 41 · Good41
Median AQI
71
90th Percentile
169
Max AQI
263
Days with Data
Ranked #8 of 23 counties in Illinois (by median AQI, lower is better)
Monthly Median AQI — 2025
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41
Median AQI
71
90th Percentile
169
Max AQI
263
Days with Data
Ranked #8 of 23 counties in Illinois (by median AQI, lower is better)
Click a bar to view that month's details