Houston Air Quality in October

Across 2019–2025, Houston's October air quality had a median AQI of 62 (Moderate) over 217 monitored days in the Houston-The Woodlands-Sugar Land, TX area. 18.0% of October days (39 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 46.1% of days. The cleanest October on record here was 2023 (median AQI 57, 1 day above 100) and the worst was 2024 (median 82, 11 days above 100, peak AQI 192).

62
Median AQI
Moderate
18.0%
Days above AQI 100
39 of 217 days
119
90th percentile AQI
worst 1 day in 10
192
Peak AQI
Unhealthy
PM2.5
Main pollutant
46.1% of days
17.1%
Good days
37 of 217
  • Good: 17.1%
  • Moderate: 65.0%
  • Unhealthy for Sensitive Groups: 15.7%
  • Unhealthy or worse: 2.3%

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QUICK ANSWER

How is the air in Houston in October?

Moderate on a typical day: median AQI 62 across 2019–2025, with 18.0% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 17.1% of October days were Good (AQI 0–50), 65.0% Moderate (51–100).
  • 39 days of 217 reached AQI 101+; the October peak was 192.
  • Best October: 2023; worst October: 2024.

Frequently asked questions

What is the air quality like in Houston in October?

Across 2019–2025, the median daily AQI in Houston in October was 62 (Moderate). 17.1% of days were Good, 65.0% Moderate, and 18.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is October a good time for outdoor exercise in Houston?

A typical October day in Houston 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 6 of October days (18.0%) 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 October air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 46.1% of October days in Houston. The highest October AQI recorded in 2019–2025 was 192 (Unhealthy), in 2024.

Houston October air quality, year by year

Houston October air quality by year (Houston-The Woodlands-Sugar Land, TX, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931532140PM2.5
202031575140PM2.5
202131664166PM2.5
202231799154O3
2023cleanest31571101PM2.5
2024worst318211192O3
202531647151O3

What October air means in Houston

A typical October day in Houston 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 6 of October days (18.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

October's median AQI of 62 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 October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Houston runs above the national October norm; 18.0% of its October days topped AQI 100 versus 1.3% nationally (above average).

October is part of Houston's fall season (September, October, November); the fall 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 57 (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.