Brownsville Air Quality in December
Across 2019–2025, Brownsville's December air quality had a median AQI of 51 (Moderate) over 217 monitored days in the Brownsville-Harlingen, TX area. 0.5% of December days (1 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 79.7% of days. The cleanest December on record here was 2022 (median AQI 40, 0 days above 100) and the worst was 2025 (median 58, 1 day above 100, peak AQI 109).
- Good: 48.8%
- Moderate: 50.7%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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How is the air in Brownsville in December?
Moderate on a typical day: median AQI 51 across 2019–2025, with 0.5% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓48.8% of December days were Good (AQI 0–50), 50.7% Moderate (51–100).
- ✓1 day of 217 reached AQI 101+; the December peak was 109.
- ✓Best December: 2022; worst December: 2025.
Frequently asked questions
What is the air quality like in Brownsville in December?▾
Across 2019–2025, the median daily AQI in Brownsville in December was 51 (Moderate). 48.8% of days were Good, 50.7% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is December a good time for outdoor exercise in Brownsville?▾
A typical December 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 December 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 December air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 79.7% of December days in Brownsville. The highest December AQI recorded in 2019–2025 was 109 (Unhealthy for Sensitive Groups), in 2025.
Brownsville December air quality, year by year
Brownsville December 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 | 46 | 0 | 72 | PM2.5 |
| 2020 | 31 | 41 | 0 | 76 | PM2.5 |
| 2021 | 31 | 46 | 0 | 92 | PM2.5 |
| 2022cleanest | 31 | 40 | 0 | 70 | PM2.5 |
| 2023 | 31 | 52 | 0 | 96 | PM2.5 |
| 2024 | 31 | 55 | 0 | 94 | PM2.5 |
| 2025worst | 31 | 58 | 1 | 109 | PM2.5 |
What December air means in Brownsville
A typical December 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 December days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
December'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 December AQI across every EPA metro area (95,590 metro-days, 2019–2025) is 39, so Brownsville runs above the national December norm; 0.5% of its December days topped AQI 100 versus 0.7% nationally (about the same).
December is part of Brownsville's winter season (December, January, February); the winter 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.