Indianapolis Air Quality in Winter
Across 2019–2025, Indianapolis's winter (December–February) air quality had a median AQI of 57 (Moderate) over 632 monitored days in the Indianapolis-Carmel-Anderson, IN area. 0.6% of winter days (4 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 96.8% of days. The cleanest winter on record here was 2024 (median AQI 54, 0 days above 100) and the worst was 2022 (median 59, 2 days above 100, peak AQI 107).
- Good: 25.2%
- Moderate: 74.2%
- Unhealthy for Sensitive Groups: 0.6%
- Unhealthy or worse: 0.0%
Extra Protection for Indianapolis Homes
Air quality in Indianapolis is moderate (AQI 55), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How is the air in Indianapolis in winter?
Moderate on a typical day: median AQI 57 across 2019–2025, with 0.6% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓25.2% of winter days were Good (AQI 0–50), 74.2% Moderate (51–100).
- ✓4 days of 632 reached AQI 101+; the winter peak was 126.
- ✓Cleanest month: February; worst month: December.
Frequently asked questions
What is the air quality like in Indianapolis in winter?▾
Across 2019–2025, the median daily AQI in Indianapolis in winter was 57 (Moderate). 25.2% of days were Good, 74.2% Moderate, and 0.6% 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 Indianapolis?▾
A typical winter day in Indianapolis is Moderate (median AQI 57): 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 Indianapolis's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 96.8% of winter days in Indianapolis. The highest winter AQI recorded in 2019–2025 was 126 (Unhealthy for Sensitive Groups), in 2022.
Indianapolis winter air quality, year by year
Indianapolis winter air quality by year (Indianapolis-Carmel-Anderson, IN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 59 | 0 | 93 | PM2.5 |
| 2020 | 91 | 58 | 1 | 101 | PM2.5 |
| 2021 | 90 | 60 | 0 | 98 | PM2.5 |
| 2022worst | 90 | 59 | 2 | 107 | PM2.5 |
| 2023 | 90 | 58 | 1 | 126 | PM2.5 |
| 2024cleanest | 91 | 54 | 0 | 92 | PM2.5 |
| 2025 | 90 | 54 | 0 | 86 | PM2.5 |
What winter air means in Indianapolis
A typical winter day in Indianapolis is Moderate (median AQI 57): 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 57 is in line with Indianapolis's whole-year median of 56, 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 Indianapolis runs above the national Winter norm; 0.6% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, February is the cleanest month (median AQI 58, 0.0% of days above 100) and December the worst (median 58, 0.9% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Indianapolis
The latest EPA AirNow observation puts Indianapolis's AQI at 55 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Indianapolis air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Indianapolis-Carmel-Anderson, IN), 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.