Brownsville Air Quality in October
Across 2019–2025, Brownsville's October air quality had a median AQI of 48 (Good) over 217 monitored days in the Brownsville-Harlingen, TX area. 0.9% of October days (2 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 66.8% of days. The cleanest October on record here was 2020 (median AQI 38, 0 days above 100) and the worst was 2025 (median 62, 2 days above 100, peak AQI 123).
- Good: 54.4%
- Moderate: 44.7%
- Unhealthy for Sensitive Groups: 0.9%
- Unhealthy or worse: 0.0%
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How is the air in Brownsville in October?
Good on a typical day: median AQI 48 across 2019–2025, with 0.9% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓54.4% of October days were Good (AQI 0–50), 44.7% Moderate (51–100).
- ✓2 days of 217 reached AQI 101+; the October peak was 123.
- ✓Best October: 2020; worst October: 2025.
Frequently asked questions
What is the air quality like in Brownsville in October?▾
Across 2019–2025, the median daily AQI in Brownsville in October was 48 (Good). 54.4% of days were Good, 44.7% Moderate, and 0.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Brownsville?▾
A typical October day in Brownsville sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
Which pollutant causes Brownsville's October air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 66.8% of October days in Brownsville. The highest October AQI recorded in 2019–2025 was 123 (Unhealthy for Sensitive Groups), in 2025.
Brownsville October air quality, year by year
Brownsville October air quality by year (Brownsville-Harlingen, TX, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 41 | 0 | 65 | PM2.5 |
| 2020cleanest | 31 | 38 | 0 | 69 | PM2.5 |
| 2021 | 31 | 42 | 0 | 76 | PM2.5 |
| 2022 | 31 | 43 | 0 | 64 | O3 |
| 2023 | 31 | 43 | 0 | 67 | PM2.5 |
| 2024 | 31 | 59 | 0 | 96 | PM2.5 |
| 2025worst | 31 | 62 | 2 | 123 | PM2.5 |
What October air means in Brownsville
A typical October day in Brownsville sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
October's median AQI of 48 is below Brownsville's whole-year median of 52, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Brownsville runs above the national October norm; 0.9% of its October days topped AQI 100 versus 1.3% nationally (about the same).
October is part of Brownsville's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Brownsville
The latest EPA AirNow observation puts Brownsville's AQI at 47 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Brownsville air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Brownsville-Harlingen, 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.