Rockford Air Quality in March

Across 2019–2025, Rockford's March air quality had a median AQI of 43 (Good) over 217 monitored days in the Rockford, IL area. 0.0% of March days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 56.2% of days. The cleanest March on record here was 2025 (median AQI 36, 0 days above 100) and the worst was 2020 (median 51, 0 days above 100, peak AQI 67).

43
Median AQI
Good
0.0%
Days above AQI 100
0 of 217 days
62
90th percentile AQI
worst 1 day in 10
85
Peak AQI
Moderate
PM2.5
Main pollutant
56.2% of days
62.2%
Good days
135 of 217
  • Good: 62.2%
  • Moderate: 37.8%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Rockford in March?

Good on a typical day: median AQI 43 across 2019–2025, with 0.0% of March days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 62.2% of March days were Good (AQI 0–50), 37.8% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the March peak was 85.
  • Best March: 2025; worst March: 2020.

Frequently asked questions

What is the air quality like in Rockford in March?

Across 2019–2025, the median daily AQI in Rockford in March was 43 (Good). 62.2% of days were Good, 37.8% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is March a good time for outdoor exercise in Rockford?

A typical March day in Rockford sits in the Good range (median AQI 43), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.

Which pollutant causes Rockford's March air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 56.2% of March days in Rockford. The highest March AQI recorded in 2019–2025 was 85 (Moderate), in 2020.

Rockford March air quality, year by year

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

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193151083PM2.5
2020worst3151067PM2.5
20213147074PM2.5
20223140085PM2.5
20233149071PM2.5
20243137058O3
2025cleanest3136069O3

What March air means in Rockford

A typical March day in Rockford sits in the Good range (median AQI 43), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.

March's median AQI of 43 is below Rockford's whole-year median of 47, making it one of the area's cleaner periods. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so Rockford runs in line with the national March norm; 0.0% of its March days topped AQI 100 versus 0.4% nationally (about the same).

March is part of Rockford's spring season (March, April, May); the spring 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.