Brownsville Air Quality in May
Across 2019–2025, Brownsville's May air quality had a median AQI of 62 (Moderate) over 217 monitored days in the Brownsville-Harlingen, TX area. 13.8% of May days (30 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 90.3% of days. The cleanest May on record here was 2021 (median AQI 55, 0 days above 100) and the worst was 2024 (median 124, 24 days above 100, peak AQI 171).
- Good: 17.1%
- Moderate: 69.1%
- Unhealthy for Sensitive Groups: 10.6%
- Unhealthy or worse: 3.2%
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How is the air in Brownsville in May?
Moderate on a typical day: median AQI 62 across 2019–2025, with 13.8% of May days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓17.1% of May days were Good (AQI 0–50), 69.1% Moderate (51–100).
- ✓30 days of 217 reached AQI 101+; the May peak was 171.
- ✓Best May: 2021; worst May: 2024.
Frequently asked questions
What is the air quality like in Brownsville in May?▾
Across 2019–2025, the median daily AQI in Brownsville in May was 62 (Moderate). 17.1% of days were Good, 69.1% Moderate, and 13.8% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is May a good time for outdoor exercise in Brownsville?▾
A typical May day in Brownsville is Moderate (median AQI 62): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 7 of May days (13.8%) 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 May air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 90.3% of May days in Brownsville. The highest May AQI recorded in 2019–2025 was 171 (Unhealthy), in 2024.
Brownsville May air quality, year by year
Brownsville May 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 | 59 | 0 | 87 | PM2.5 |
| 2020 | 31 | 56 | 0 | 76 | PM2.5 |
| 2021cleanest | 31 | 55 | 0 | 79 | PM2.5 |
| 2022 | 31 | 61 | 0 | 92 | PM2.5 |
| 2023 | 31 | 56 | 3 | 141 | PM2.5 |
| 2024worst | 31 | 124 | 24 | 171 | PM2.5 |
| 2025 | 31 | 64 | 3 | 139 | PM2.5 |
What May air means in Brownsville
A typical May day in Brownsville is Moderate (median AQI 62): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 7 of May days (13.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
May's median AQI of 62 is above Brownsville's whole-year median of 52, making it one of the area's dirtier periods. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Brownsville runs above the national May norm; 13.8% of its May days topped AQI 100 versus 1.3% nationally (above average).
May is part of Brownsville's spring season (March, April, May); the spring 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 43 (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.