St. Paul Air Quality in Summer
Across 2019–2025, St. Paul's summer (June–August) air quality had a median AQI of 54 (Moderate) over 644 monitored days in the Minneapolis-St. Paul-Bloomington, MN-WI area. 6.5% of summer days (42 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 50.8% of days. The cleanest summer on record here was 2022 (median AQI 49, 0 days above 100) and the worst was 2023 (median 72, 18 days above 100, peak AQI 190).
- Good: 39.4%
- Moderate: 54.0%
- Unhealthy for Sensitive Groups: 4.3%
- Unhealthy or worse: 2.2%
Reduce Indoor Ozone in St. Paul
Today's main pollutant in St. Paul is ground-level ozone (AQI 25). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in St. Paul in summer?
Moderate on a typical day: median AQI 54 across 2019–2025, with 6.5% of summer days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓39.4% of summer days were Good (AQI 0–50), 54.0% Moderate (51–100).
- ✓42 days of 644 reached AQI 101+; the summer peak was 193.
- ✓Cleanest month: August; worst month: June.
Frequently asked questions
What is the air quality like in St. Paul in summer?▾
Across 2019–2025, the median daily AQI in St. Paul in summer was 54 (Moderate). 39.4% of days were Good, 54.0% Moderate, and 6.5% 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 St. Paul?▾
A typical summer day in St. Paul is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 15 of summer days (6.5%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes St. Paul's summer air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 50.8% of summer days in St. Paul. The highest summer AQI recorded in 2019–2025 was 193 (Unhealthy), in 2023.
St. Paul summer air quality, year by year
St. Paul summer air quality by year (Minneapolis-St. Paul-Bloomington, MN-WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 52 | 1 | 122 | PM2.5 |
| 2020 | 92 | 51 | 3 | 163 | PM2.5 |
| 2021 | 92 | 61 | 8 | 193 | O3 |
| 2022cleanest | 92 | 49 | 0 | 93 | O3 |
| 2023worst | 92 | 72 | 18 | 190 | PM2.5 |
| 2024 | 92 | 51 | 1 | 101 | PM2.5 |
| 2025 | 92 | 58 | 11 | 178 | PM2.5 |
What summer air means in St. Paul
A typical summer day in St. Paul is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 15 of summer days (6.5%) 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 54 is above St. Paul's whole-year median of 50, 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 St. Paul runs above the national Summer norm; 6.5% of its Summer days topped AQI 100 versus 3.6% nationally (above average).
Within the season, August is the cleanest month (median AQI 52, 1.4% of days above 100) and June the worst (median 54, 9.5% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in St. Paul
The latest EPA AirNow observation puts St. Paul's AQI at 25 (O3). The figures above are multi-year season statistics, not today's reading.
View current St. Paul air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Minneapolis-St. Paul-Bloomington, MN-WI), 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.