Sioux Falls Air Quality in Winter
Across 2019–2025, Sioux Falls's winter (December–February) air quality had a median AQI of 33 (Good) over 632 monitored days in the Sioux Falls, SD area. 0.0% of winter days (0 of 632) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 53.8% of days. The cleanest winter on record here was 2024 (median AQI 26, 0 days above 100) and the worst was 2023 (median 36, 0 days above 100, peak AQI 94).
- Good: 86.6%
- Moderate: 13.4%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Sioux Falls
Today's main pollutant in Sioux Falls is ground-level ozone (AQI 24). 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
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How is the air in Sioux Falls in winter?
Good on a typical day: median AQI 33 across 2019–2025, with 0.0% of winter days above AQI 100. Ground-level ozone is the main driver.
- ✓86.6% of winter days were Good (AQI 0–50), 13.4% Moderate (51–100).
- ✓0 days of 632 reached AQI 101+; the winter peak was 94.
- ✓Cleanest month: December; worst month: February.
Frequently asked questions
What is the air quality like in Sioux Falls in winter?▾
Across 2019–2025, the median daily AQI in Sioux Falls in winter was 33 (Good). 86.6% of days were Good, 13.4% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Sioux Falls?▾
A typical winter day in Sioux Falls sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Which pollutant causes Sioux Falls's winter air quality problems?▾
Ground-level ozone set the daily AQI on 53.8% of winter days in Sioux Falls. The highest winter AQI recorded in 2019–2025 was 94 (Moderate), in 2023.
Sioux Falls winter air quality, year by year
Sioux Falls winter air quality by year (Sioux Falls, SD, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 34 | 0 | 80 | PM2.5 |
| 2020 | 91 | 36 | 0 | 86 | PM2.5 |
| 2021 | 90 | 32 | 0 | 91 | O3 |
| 2022 | 90 | 32 | 0 | 64 | O3 |
| 2023worst | 90 | 36 | 0 | 94 | O3 |
| 2024cleanest | 91 | 26 | 0 | 66 | O3 |
| 2025 | 90 | 32 | 0 | 55 | O3 |
What winter air means in Sioux Falls
A typical winter day in Sioux Falls sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Winter's median AQI of 33 is below Sioux Falls's whole-year median of 38, making it one of the area's cleaner periods. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Sioux Falls runs below the national Winter norm; 0.0% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, December is the cleanest month (median AQI 30, 0.0% of days above 100) and February the worst (median 36, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Sioux Falls
The latest EPA AirNow observation puts Sioux Falls's AQI at 24 (O3). The figures above are multi-year season statistics, not today's reading.
View current Sioux Falls air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Sioux Falls, SD), 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.