Brownsville Air Quality in August

Across 2019–2025, Brownsville's August air quality had a median AQI of 51 (Moderate) over 217 monitored days in the Brownsville-Harlingen, TX area. 0.5% of August days (1 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 91.2% of days. The cleanest August on record here was 2025 (median AQI 41, 0 days above 100) and the worst was 2023 (median 54, 1 day above 100, peak AQI 101).

51
Median AQI
Moderate
0.5%
Days above AQI 100
1 of 217 days
63
90th percentile AQI
worst 1 day in 10
101
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
91.2% of days
47.5%
Good days
103 of 217
  • Good: 47.5%
  • Moderate: 52.1%
  • Unhealthy for Sensitive Groups: 0.5%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Brownsville in August?

Moderate on a typical day: median AQI 51 across 2019–2025, with 0.5% of August days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 47.5% of August days were Good (AQI 0–50), 52.1% Moderate (51–100).
  • 1 day of 217 reached AQI 101+; the August peak was 101.
  • Best August: 2025; worst August: 2023.

Frequently asked questions

What is the air quality like in Brownsville in August?

Across 2019–2025, the median daily AQI in Brownsville in August was 51 (Moderate). 47.5% of days were Good, 52.1% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is August a good time for outdoor exercise in Brownsville?

A typical August day in Brownsville is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of August 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 Brownsville's August air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 91.2% of August days in Brownsville. The highest August AQI recorded in 2019–2025 was 101 (Unhealthy for Sensitive Groups), in 2023.

Brownsville August air quality, year by year

Brownsville August air quality by year (Brownsville-Harlingen, TX, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193154079PM2.5
20203152070PM2.5
20213152073PM2.5
20223144070PM2.5
2023worst31541101PM2.5
20243147064PM2.5
2025cleanest3141087PM2.5

What August air means in Brownsville

A typical August day in Brownsville is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of August days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

August's median AQI of 51 is in line with Brownsville's whole-year median of 52, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Brownsville runs above the national August norm; 0.5% of its August days topped AQI 100 versus 3.5% nationally (below average).

August is part of Brownsville's summer season (June, July, August); the summer 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.