Houston Air Quality in March
Across 2019–2025, Houston's March air quality had a median AQI of 59 (Moderate) over 217 monitored days in the Houston-The Woodlands-Sugar Land, TX area. 3.7% of March days (8 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 65.9% of days. The cleanest March on record here was 2020 (median AQI 56, 0 days above 100) and the worst was 2025 (median 69, 3 days above 100, peak AQI 179).
- Good: 17.1%
- Moderate: 79.3%
- Unhealthy for Sensitive Groups: 2.8%
- Unhealthy or worse: 0.9%
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How is the air in Houston in March?
Moderate on a typical day: median AQI 59 across 2019–2025, with 3.7% of March days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓17.1% of March days were Good (AQI 0–50), 79.3% Moderate (51–100).
- ✓8 days of 217 reached AQI 101+; the March peak was 179.
- ✓Best March: 2020; worst March: 2025.
Frequently asked questions
What is the air quality like in Houston in March?▾
Across 2019–2025, the median daily AQI in Houston in March was 59 (Moderate). 17.1% of days were Good, 79.3% Moderate, and 3.7% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is March a good time for outdoor exercise in Houston?▾
A typical March day in Houston is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 27 of March days (3.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Houston's March air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 65.9% of March days in Houston. The highest March AQI recorded in 2019–2025 was 179 (Unhealthy), in 2025.
Houston March air quality, year by year
Houston March air quality by year (Houston-The Woodlands-Sugar Land, TX, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 58 | 3 | 129 | PM2.5 |
| 2020cleanest | 31 | 56 | 0 | 84 | PM2.5 |
| 2021 | 31 | 57 | 0 | 95 | PM2.5 |
| 2022 | 31 | 58 | 1 | 108 | PM2.5 |
| 2023 | 31 | 66 | 1 | 121 | PM2.5 |
| 2024 | 31 | 59 | 0 | 100 | PM2.5 |
| 2025worst | 31 | 69 | 3 | 179 | PM2.5 |
What March air means in Houston
A typical March day in Houston is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 27 of March days (3.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
March's median AQI of 59 is in line with Houston's whole-year median of 61, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so Houston runs above the national March norm; 3.7% of its March days topped AQI 100 versus 0.4% nationally (above average).
March is part of Houston's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Houston
The latest EPA AirNow observation puts Houston's AQI at 47 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Houston air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Houston-The Woodlands-Sugar Land, 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.