Dayton Air Quality in Winter
Across 2019–2025, Dayton's winter (December–February) air quality had a median AQI of 52 (Moderate) over 632 monitored days in the Dayton, OH 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 90.8% of days. The cleanest winter on record here was 2024 (median AQI 41, 0 days above 100) and the worst was 2019 (median 56, 0 days above 100, peak AQI 95).
- Good: 47.0%
- Moderate: 53.0%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Improve Indoor Air Quality
Even with good outdoor air in Dayton, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
Recommended: Levoit Core 400S — True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Dayton in winter?
Moderate on a typical day: median AQI 52 across 2019–2025, with 0.0% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓47.0% of winter days were Good (AQI 0–50), 53.0% Moderate (51–100).
- ✓0 days of 632 reached AQI 101+; the winter peak was 96.
- ✓Cleanest month: January; worst month: February.
Frequently asked questions
What is the air quality like in Dayton in winter?▾
Across 2019–2025, the median daily AQI in Dayton in winter was 52 (Moderate). 47.0% of days were Good, 53.0% 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 Dayton?▾
A typical winter day in Dayton is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of winter days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Dayton's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 90.8% of winter days in Dayton. The highest winter AQI recorded in 2019–2025 was 96 (Moderate), in 2019.
Dayton winter air quality, year by year
Dayton winter air quality by year (Dayton, OH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 90 | 56 | 0 | 95 | PM2.5 |
| 2020 | 91 | 54 | 0 | 90 | PM2.5 |
| 2021 | 90 | 53 | 0 | 96 | PM2.5 |
| 2022 | 90 | 49 | 0 | 88 | PM2.5 |
| 2023 | 90 | 48 | 0 | 70 | PM2.5 |
| 2024cleanest | 91 | 41 | 0 | 77 | PM2.5 |
| 2025 | 90 | 46 | 0 | 77 | PM2.5 |
What winter air means in Dayton
A typical winter day in Dayton is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of winter days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Winter's median AQI of 52 is in line with Dayton's whole-year median of 51, 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 Dayton runs above 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 51, 0.0% of days above 100) and February the worst (median 53, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Dayton
The latest EPA AirNow observation puts Dayton's AQI at 50 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Dayton air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Dayton, OH), 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.