Houston Air Quality in Winter
Across 2019–2025, Houston's winter (December–February) air quality had a median AQI of 56 (Moderate) over 632 monitored days in the Houston-The Woodlands-Sugar Land, TX area. 1.9% of winter days (12 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 85.0% of days. The cleanest winter on record here was 2022 (median AQI 59, 0 days above 100) and the worst was 2023 (median 61, 3 days above 100, peak AQI 122).
- Good: 25.0%
- Moderate: 73.1%
- Unhealthy for Sensitive Groups: 1.3%
- Unhealthy or worse: 0.6%
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How is the air in Houston in winter?
Moderate on a typical day: median AQI 56 across 2019–2025, with 1.9% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓25.0% of winter days were Good (AQI 0–50), 73.1% Moderate (51–100).
- ✓12 days of 632 reached AQI 101+; the winter peak was 190.
- ✓Cleanest month: February; worst month: January.
Frequently asked questions
What is the air quality like in Houston in winter?▾
Across 2019–2025, the median daily AQI in Houston in winter was 56 (Moderate). 25.0% of days were Good, 73.1% Moderate, and 1.9% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Houston?▾
A typical winter day in Houston is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 53 of winter days (1.9%) 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 winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 85.0% of winter days in Houston. The highest winter AQI recorded in 2019–2025 was 190 (Unhealthy), in 2023.
Houston winter air quality, year by year
Houston winter 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 | 90 | 54 | 2 | 176 | PM2.5 |
| 2020 | 91 | 53 | 1 | 190 | PM2.5 |
| 2021 | 90 | 54 | 2 | 130 | PM2.5 |
| 2022cleanest | 90 | 59 | 0 | 84 | PM2.5 |
| 2023worst | 90 | 61 | 3 | 122 | PM2.5 |
| 2024 | 91 | 57 | 2 | 184 | PM2.5 |
| 2025 | 90 | 59 | 2 | 168 | PM2.5 |
What winter air means in Houston
A typical winter day in Houston is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 53 of winter days (1.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Winter's median AQI of 56 is below Houston's whole-year median of 61, making it one of the area's cleaner periods. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Houston runs above the national Winter norm; 1.9% of its Winter days topped AQI 100 versus 0.6% nationally (above average).
Within the season, February is the cleanest month (median AQI 57, 0.5% of days above 100) and January the worst (median 55, 4.1% above 100).
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 season 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.