Rockford Air Quality in Spring
Across 2019–2025, Rockford's spring (March–May) air quality had a median AQI of 44 (Good) over 644 monitored days in the Rockford, IL area. 0.5% of spring days (3 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 58.1% of days. The cleanest spring on record here was 2025 (median AQI 40, 0 days above 100) and the worst was 2023 (median 51, 3 days above 100, peak AQI 133).
- Good: 66.6%
- Moderate: 32.9%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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How is the air in Rockford in spring?
Good on a typical day: median AQI 44 across 2019–2025, with 0.5% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓66.6% of spring days were Good (AQI 0–50), 32.9% Moderate (51–100).
- ✓3 days of 644 reached AQI 101+; the spring peak was 133.
- ✓Cleanest month: March; worst month: May.
Frequently asked questions
What is the air quality like in Rockford in spring?▾
Across 2019–2025, the median daily AQI in Rockford in spring was 44 (Good). 66.6% of days were Good, 32.9% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Rockford?▾
A typical spring day in Rockford sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Which pollutant causes Rockford's spring air quality problems?▾
Ground-level ozone set the daily AQI on 58.1% of spring days in Rockford. The highest spring AQI recorded in 2019–2025 was 133 (Unhealthy for Sensitive Groups), in 2023.
Rockford spring air quality, year by year
Rockford spring air quality by year (Rockford, IL, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 48 | 0 | 83 | O3 |
| 2020 | 92 | 44 | 0 | 74 | PM2.5 |
| 2021 | 92 | 44 | 0 | 80 | O3 |
| 2022 | 92 | 42 | 0 | 85 | O3 |
| 2023worst | 92 | 51 | 3 | 133 | O3 |
| 2024 | 92 | 43 | 0 | 71 | O3 |
| 2025cleanest | 92 | 40 | 0 | 80 | O3 |
What spring air means in Rockford
A typical spring day in Rockford sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Spring's median AQI of 44 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 Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Rockford runs in line with the national Spring norm; 0.5% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, March is the cleanest month (median AQI 43, 0.0% of days above 100) and May the worst (median 44, 1.4% 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.