Des Moines Air Quality in May
Across 2019–2025, Des Moines's May air quality had a median AQI of 45 (Good) over 217 monitored days in the Des Moines-West Des Moines, IA area. 0.5% of May days (1 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 74.7% of days. The cleanest May on record here was 2019 (median AQI 39, 0 days above 100) and the worst was 2023 (median 59, 1 day above 100, peak AQI 101).
- Good: 71.0%
- Moderate: 28.6%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
Improve Indoor Air Quality
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How is the air in Des Moines in May?
Good on a typical day: median AQI 45 across 2019–2025, with 0.5% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓71.0% of May days were Good (AQI 0–50), 28.6% Moderate (51–100).
- ✓1 day of 217 reached AQI 101+; the May peak was 101.
- ✓Best May: 2019; worst May: 2023.
Frequently asked questions
What is the air quality like in Des Moines in May?▾
Across 2019–2025, the median daily AQI in Des Moines in May was 45 (Good). 71.0% of days were Good, 28.6% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is May a good time for outdoor exercise in Des Moines?▾
A typical May day in Des Moines sits in the Good range (median AQI 45), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
Which pollutant causes Des Moines's May air quality problems?▾
Ground-level ozone set the daily AQI on 74.7% of May days in Des Moines. The highest May AQI recorded in 2019–2025 was 101 (Unhealthy for Sensitive Groups), in 2023.
Des Moines May air quality, year by year
Des Moines May 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 |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 39 | 0 | 97 | O3 |
| 2020 | 31 | 39 | 0 | 49 | O3 |
| 2021 | 31 | 41 | 0 | 54 | O3 |
| 2022 | 31 | 44 | 0 | 80 | O3 |
| 2023worst | 31 | 59 | 1 | 101 | O3 |
| 2024 | 31 | 49 | 0 | 80 | O3 |
| 2025 | 31 | 46 | 0 | 87 | O3 |
What May air means in Des Moines
A typical May day in Des Moines sits in the Good range (median AQI 45), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
May's median AQI of 45 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 May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Des Moines runs in line with the national May norm; 0.5% of its May days topped AQI 100 versus 1.3% nationally (about the same).
May is part of Des Moines's spring season (March, April, May); the spring page pools all three months.
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 month 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.