Des Moines Air Quality in Winter
Across 2019–2025, Des Moines's winter (December–February) air quality had a median AQI of 42 (Good) over 632 monitored days in the Des Moines-West Des Moines, IA area. 0.0% of winter days (0 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 94.6% of days. The cleanest winter on record here was 2025 (median AQI 35, 0 days above 100) and the worst was 2019 (median 52, 0 days above 100, peak AQI 79).
- Good: 63.4%
- Moderate: 36.6%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Des Moines in winter?
Good on a typical day: median AQI 42 across 2019–2025, with 0.0% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓63.4% of winter days were Good (AQI 0–50), 36.6% Moderate (51–100).
- ✓0 days of 632 reached AQI 101+; the winter peak was 91.
- ✓Cleanest month: January; worst month: December.
Frequently asked questions
What is the air quality like in Des Moines in winter?▾
Across 2019–2025, the median daily AQI in Des Moines in winter was 42 (Good). 63.4% of days were Good, 36.6% 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 Des Moines?▾
A typical winter day in Des Moines sits in the Good range (median AQI 42), 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 Des Moines's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 94.6% of winter days in Des Moines. The highest winter AQI recorded in 2019–2025 was 91 (Moderate), in 2019.
Des Moines winter air quality, year by year
Des Moines winter air quality by year (Des Moines-West Des Moines, IA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 90 | 52 | 0 | 79 | PM2.5 |
| 2020 | 91 | 47 | 0 | 76 | PM2.5 |
| 2021 | 90 | 47 | 0 | 84 | PM2.5 |
| 2022 | 90 | 39 | 0 | 89 | PM2.5 |
| 2023 | 90 | 44 | 0 | 91 | PM2.5 |
| 2024 | 91 | 39 | 0 | 71 | PM2.5 |
| 2025cleanest | 90 | 35 | 0 | 76 | PM2.5 |
What winter air means in Des Moines
A typical winter day in Des Moines sits in the Good range (median AQI 42), 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 42 is in line with Des Moines's whole-year median of 44, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Des Moines runs in line with the national Winter norm; 0.0% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, January is the cleanest month (median AQI 41, 0.0% of days above 100) and December the worst (median 43, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Des Moines
The latest EPA AirNow observation puts Des Moines's AQI at 32 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Des Moines air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Des Moines-West Des Moines, IA), 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.