Tacoma Air Quality in October

Across 2019–2025, Tacoma's October air quality had a median AQI of 53 (Moderate) over 217 monitored days in the Seattle-Tacoma-Bellevue, WA area. 6.0% of October days (13 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 86.2% of days. The cleanest October on record here was 2021 (median AQI 46, 0 days above 100) and the worst was 2022 (median 85, 13 days above 100, peak AQI 362).

53
Median AQI
Moderate
6.0%
Days above AQI 100
13 of 217 days
81
90th percentile AQI
worst 1 day in 10
362
Peak AQI
Hazardous
PM2.5
Main pollutant
86.2% of days
42.9%
Good days
93 of 217
  • Good: 42.9%
  • Moderate: 51.2%
  • Unhealthy for Sensitive Groups: 2.3%
  • Unhealthy or worse: 3.7%

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QUICK ANSWER

How is the air in Tacoma in October?

Moderate on a typical day: median AQI 53 across 2019–2025, with 6.0% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 42.9% of October days were Good (AQI 0–50), 51.2% Moderate (51–100).
  • 13 days of 217 reached AQI 101+; the October peak was 362.
  • Best October: 2021; worst October: 2022.

Frequently asked questions

What is the air quality like in Tacoma in October?

Across 2019–2025, the median daily AQI in Tacoma in October was 53 (Moderate). 42.9% of days were Good, 51.2% Moderate, and 6.0% 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 Tacoma?

A typical October day in Tacoma is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 17 of October days (6.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Tacoma's October air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 86.2% of October days in Tacoma. The highest October AQI recorded in 2019–2025 was 362 (Hazardous), in 2022.

Tacoma October air quality, year by year

Tacoma October air quality by year (Seattle-Tacoma-Bellevue, WA, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193156086PM2.5
20203153081PM2.5
2021cleanest3146088PM2.5
2022worst318513362PM2.5
20233152087PM2.5
20243149096PM2.5
20253151061PM2.5

What October air means in Tacoma

A typical October day in Tacoma is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 17 of October days (6.0%) 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 53 is above Tacoma's whole-year median of 49, making it one of the area's dirtier periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Tacoma runs above the national October norm; 6.0% of its October days topped AQI 100 versus 1.3% nationally (above average).

October is part of Tacoma's fall season (September, October, November); the fall page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Tacoma

The latest EPA AirNow observation puts Tacoma's AQI at 41 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Tacoma air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Seattle-Tacoma-Bellevue, WA), 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.