McAllen Air Quality in September
Across 2019–2025, McAllen's September air quality had a median AQI of 41 (Good) over 210 monitored days in the McAllen-Edinburg-Mission, TX area. 0.5% of September days (1 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 72.9% of days. The cleanest September on record here was 2023 (median AQI 32, 0 days above 100) and the worst was 2021 (median 53, 1 day above 100, peak AQI 105).
- Good: 71.4%
- Moderate: 28.1%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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How is the air in McAllen in September?
Good on a typical day: median AQI 41 across 2019–2025, with 0.5% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓71.4% of September days were Good (AQI 0–50), 28.1% Moderate (51–100).
- ✓1 day of 210 reached AQI 101+; the September peak was 105.
- ✓Best September: 2023; worst September: 2021.
Frequently asked questions
What is the air quality like in McAllen in September?▾
Across 2019–2025, the median daily AQI in McAllen in September was 41 (Good). 71.4% of days were Good, 28.1% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is September a good time for outdoor exercise in McAllen?▾
A typical September day in McAllen sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
Which pollutant causes McAllen's September air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 72.9% of September days in McAllen. The highest September AQI recorded in 2019–2025 was 105 (Unhealthy for Sensitive Groups), in 2021.
McAllen September air quality, year by year
McAllen September air quality by year (McAllen-Edinburg-Mission, TX, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 38 | 0 | 61 | PM2.5 |
| 2020 | 30 | 47 | 0 | 86 | PM2.5 |
| 2021worst | 30 | 53 | 1 | 105 | PM2.5 |
| 2022 | 30 | 40 | 0 | 100 | O3 |
| 2023cleanest | 30 | 32 | 0 | 59 | PM2.5 |
| 2024 | 30 | 34 | 0 | 66 | PM2.5 |
| 2025 | 30 | 41 | 0 | 71 | O3 |
What September air means in McAllen
A typical September day in McAllen sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
September's median AQI of 41 is below McAllen's whole-year median of 50, making it one of the area's cleaner periods. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so McAllen runs in line with the national September norm; 0.5% of its September days topped AQI 100 versus 2.7% nationally (below average).
September is part of McAllen's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in McAllen
The latest EPA AirNow observation puts McAllen's AQI at 47 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current McAllen air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (McAllen-Edinburg-Mission, 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.