San Antonio Air Quality in Fall
Across 2019–2025, San Antonio's fall (September–November) air quality had a median AQI of 52 (Moderate) over 637 monitored days in the San Antonio-New Braunfels, TX area. 5.7% of fall days (36 of 637) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 51.2% of days. The cleanest fall on record here was 2019 (median AQI 51, 0 days above 100) and the worst was 2022 (median 54, 8 days above 100, peak AQI 129).
- Good: 46.2%
- Moderate: 48.2%
- Unhealthy for Sensitive Groups: 5.5%
- Unhealthy or worse: 0.2%
Extra Protection for San Antonio Homes
Air quality in San Antonio is moderate (AQI 52), 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.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How is the air in San Antonio in fall?
Moderate on a typical day: median AQI 52 across 2019–2025, with 5.7% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓46.2% of fall days were Good (AQI 0–50), 48.2% Moderate (51–100).
- ✓36 days of 637 reached AQI 101+; the fall peak was 154.
- ✓Cleanest month: November; worst month: September.
Frequently asked questions
What is the air quality like in San Antonio in fall?▾
Across 2019–2025, the median daily AQI in San Antonio in fall was 52 (Moderate). 46.2% of days were Good, 48.2% Moderate, and 5.7% reached Unhealthy for Sensitive Groups or worse, based on 637 monitored days in EPA's Air Quality System.
Is fall a good time for outdoor exercise in San Antonio?▾
A typical fall day in San Antonio is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 18 of fall days (5.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes San Antonio's fall air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 51.2% of fall days in San Antonio. The highest fall AQI recorded in 2019–2025 was 154 (Unhealthy), in 2022.
San Antonio fall air quality, year by year
San Antonio fall air quality by year (San Antonio-New Braunfels, TX, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 91 | 51 | 0 | 76 | PM2.5 |
| 2020 | 91 | 54 | 4 | 122 | PM2.5 |
| 2021 | 91 | 54 | 8 | 147 | PM2.5 |
| 2022worst | 91 | 54 | 8 | 129 | O3 |
| 2023 | 91 | 48 | 5 | 136 | O3 |
| 2024 | 91 | 47 | 5 | 150 | O3 |
| 2025 | 91 | 50 | 6 | 154 | O3 |
What fall air means in San Antonio
A typical fall day in San Antonio is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 18 of fall days (5.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Fall's median AQI of 52 is in line with San Antonio's whole-year median of 55, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so San Antonio runs above the national Fall norm; 5.7% of its Fall days topped AQI 100 versus 1.5% nationally (above average).
Within the season, November is the cleanest month (median AQI 49, 0.0% of days above 100) and September the worst (median 55, 9.1% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Antonio
The latest EPA AirNow observation puts San Antonio's AQI at 52 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current San Antonio air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Antonio-New Braunfels, TX), 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.