Fargo Air Quality in September
Across 2019–2025, Fargo's September air quality had a median AQI of 37 (Good) over 209 monitored days in the Fargo, ND-MN area. 1.5% of September days (3 of 209) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 56.9% of days. The cleanest September on record here was 2019 (median AQI 26, 0 days above 100) and the worst was 2023 (median 63, 2 days above 100, peak AQI 149).
- Good: 74.2%
- Moderate: 24.4%
- Unhealthy for Sensitive Groups: 1.0%
- Unhealthy or worse: 0.5%
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How is the air in Fargo in September?
Good on a typical day: median AQI 37 across 2019–2025, with 1.5% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓74.2% of September days were Good (AQI 0–50), 24.4% Moderate (51–100).
- ✓3 days of 209 reached AQI 101+; the September peak was 158.
- ✓Best September: 2019; worst September: 2023.
Frequently asked questions
What is the air quality like in Fargo in September?▾
Across 2019–2025, the median daily AQI in Fargo in September was 37 (Good). 74.2% of days were Good, 24.4% Moderate, and 1.5% reached Unhealthy for Sensitive Groups or worse, based on 209 monitored days in EPA's Air Quality System.
Is September a good time for outdoor exercise in Fargo?▾
A typical September day in Fargo sits in the Good range (median AQI 37), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 67 of September days (1.5%) reached AQI 101+ in 2019–2025.
Which pollutant causes Fargo's September air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 56.9% of September days in Fargo. The highest September AQI recorded in 2019–2025 was 158 (Unhealthy), in 2023.
Fargo September air quality, year by year
Fargo September air quality by year (Fargo, ND-MN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 30 | 26 | 0 | 58 | O3 |
| 2020 | 29 | 29 | 0 | 64 | O3 |
| 2021 | 30 | 36 | 0 | 60 | O3 |
| 2022 | 30 | 36 | 0 | 68 | PM2.5 |
| 2023worst | 30 | 63 | 2 | 149 | PM2.5 |
| 2024 | 30 | 43 | 1 | 158 | O3 |
| 2025 | 30 | 43 | 0 | 65 | PM2.5 |
What September air means in Fargo
A typical September day in Fargo sits in the Good range (median AQI 37), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 67 of September days (1.5%) reached AQI 101+ in 2019–2025.
September's median AQI of 37 is in line with Fargo's whole-year median of 38, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so Fargo runs below the national September norm; 1.5% of its September days topped AQI 100 versus 2.7% nationally (below average).
September is part of Fargo's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Fargo, ND-MN), 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.