Rockford Air Quality in October

Across 2019–2025, Rockford's October air quality had a median AQI of 41 (Good) over 217 monitored days in the Rockford, IL area. 0.0% of October days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 70.5% of days. The cleanest October on record here was 2021 (median AQI 36, 0 days above 100) and the worst was 2020 (median 44, 0 days above 100, peak AQI 61).

41
Median AQI
Good
0.0%
Days above AQI 100
0 of 217 days
58
90th percentile AQI
worst 1 day in 10
71
Peak AQI
Moderate
PM2.5
Main pollutant
70.5% of days
69.1%
Good days
150 of 217
  • Good: 69.1%
  • Moderate: 30.9%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Rockford in October?

Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 69.1% of October days were Good (AQI 0–50), 30.9% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the October peak was 71.
  • Best October: 2021; worst October: 2020.

Frequently asked questions

What is the air quality like in Rockford in October?

Across 2019–2025, the median daily AQI in Rockford in October was 41 (Good). 69.1% of days were Good, 30.9% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is October a good time for outdoor exercise in Rockford?

A typical October day in Rockford sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.

Which pollutant causes Rockford's October air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 70.5% of October days in Rockford. The highest October AQI recorded in 2019–2025 was 71 (Moderate), in 2020.

Rockford October air quality, year by year

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

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193143063PM2.5
2020worst3144061PM2.5
2021cleanest3136071PM2.5
20223143069PM2.5
20233142068PM2.5
20243141067PM2.5
20253136071O3

What October air means in Rockford

A typical October day in Rockford sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.

October's median AQI of 41 is below Rockford's whole-year median of 47, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Rockford runs in line with the national October norm; 0.0% of its October days topped AQI 100 versus 1.3% nationally (below average).

October is part of Rockford's fall season (September, October, November); the fall 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.