Rockford Air Quality in August

Across 2019–2025, Rockford's August air quality had a median AQI of 48 (Good) over 217 monitored days in the Rockford, IL area. 0.9% of August days (2 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 66.4% of days. The cleanest August on record here was 2019 (median AQI 38, 0 days above 100) and the worst was 2025 (median 39, 2 days above 100, peak AQI 117).

48
Median AQI
Good
0.9%
Days above AQI 100
2 of 217 days
65
90th percentile AQI
worst 1 day in 10
117
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
66.4% of days
54.8%
Good days
119 of 217
  • Good: 54.8%
  • Moderate: 44.2%
  • Unhealthy for Sensitive Groups: 0.9%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Rockford in August?

Good on a typical day: median AQI 48 across 2019–2025, with 0.9% of August days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 54.8% of August days were Good (AQI 0–50), 44.2% Moderate (51–100).
  • 2 days of 217 reached AQI 101+; the August peak was 117.
  • Best August: 2019; worst August: 2025.

Frequently asked questions

What is the air quality like in Rockford in August?

Across 2019–2025, the median daily AQI in Rockford in August was 48 (Good). 54.8% of days were Good, 44.2% Moderate, and 0.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is August a good time for outdoor exercise in Rockford?

A typical August day in Rockford sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of August days reached AQI 101+ in 2019–2025.

Which pollutant causes Rockford's August air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 66.4% of August days in Rockford. The highest August AQI recorded in 2019–2025 was 117 (Unhealthy for Sensitive Groups), in 2025.

Rockford August air quality, year by year

Rockford August air quality by year (Rockford, IL, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
2019cleanest3138061O3
20203152090PM2.5
20213155090PM2.5
20223141055PM2.5
20233158072PM2.5
20243147066PM2.5
2025worst31392117PM2.5

What August air means in Rockford

A typical August day in Rockford sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of August days reached AQI 101+ in 2019–2025.

August's median AQI of 48 is in line with Rockford's whole-year median of 47, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Rockford runs in line with the national August norm; 0.9% of its August days topped AQI 100 versus 3.5% nationally (below average).

August is part of Rockford's summer season (June, July, August); the summer page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Rockford

The latest EPA AirNow observation puts Rockford's AQI at 22 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Rockford air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Rockford, IL), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.