Rockford Air Quality in Summer
Across 2019–2025, Rockford's summer (June–August) air quality had a median AQI of 51 (Moderate) over 644 monitored days in the Rockford, IL area. 3.7% of summer days (24 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 55.0% of days. The cleanest summer on record here was 2022 (median AQI 44, 0 days above 100) and the worst was 2023 (median 62, 17 days above 100, peak AQI 242).
- Good: 50.0%
- Moderate: 46.3%
- Unhealthy for Sensitive Groups: 3.1%
- Unhealthy or worse: 0.6%
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How is the air in Rockford in summer?
Moderate on a typical day: median AQI 51 across 2019–2025, with 3.7% of summer days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓50.0% of summer days were Good (AQI 0–50), 46.3% Moderate (51–100).
- ✓24 days of 644 reached AQI 101+; the summer peak was 242.
- ✓Cleanest month: August; worst month: June.
Frequently asked questions
What is the air quality like in Rockford in summer?▾
Across 2019–2025, the median daily AQI in Rockford in summer was 51 (Moderate). 50.0% of days were Good, 46.3% Moderate, and 3.7% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in Rockford?▾
A typical summer day in Rockford is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 27 of summer days (3.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Rockford's summer air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 55.0% of summer days in Rockford. The highest summer AQI recorded in 2019–2025 was 242 (Very Unhealthy), in 2023.
Rockford summer air quality, year by year
Rockford summer air quality by year (Rockford, IL, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 50 | 1 | 102 | PM2.5 |
| 2020 | 92 | 51 | 1 | 101 | PM2.5 |
| 2021 | 92 | 55 | 0 | 100 | PM2.5 |
| 2022cleanest | 92 | 44 | 0 | 97 | O3 |
| 2023worst | 92 | 62 | 17 | 242 | PM2.5 |
| 2024 | 92 | 45 | 0 | 84 | O3 |
| 2025 | 92 | 51 | 5 | 169 | PM2.5 |
What summer air means in Rockford
A typical summer day in Rockford is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 27 of summer days (3.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Summer's median AQI of 51 is above Rockford's whole-year median of 47, making it one of the area's dirtier periods. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so Rockford runs above the national Summer norm; 3.7% of its Summer days topped AQI 100 versus 3.6% nationally (about the same).
Within the season, August is the cleanest month (median AQI 48, 0.9% of days above 100) and June the worst (median 53, 7.6% above 100).
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 season 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.