Tacoma Air Quality in August

Across 2019–2025, Tacoma's August air quality had a median AQI of 47 (Good) over 217 monitored days in the Seattle-Tacoma-Bellevue, WA area. 3.7% of August days (8 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 66.4% of days. The cleanest August on record here was 2025 (median AQI 44, 0 days above 100) and the worst was 2023 (median 52, 4 days above 100, peak AQI 175).

47
Median AQI
Good
3.7%
Days above AQI 100
8 of 217 days
78
90th percentile AQI
worst 1 day in 10
175
Peak AQI
Unhealthy
PM2.5
Main pollutant
66.4% of days
58.1%
Good days
126 of 217
  • Good: 58.1%
  • Moderate: 38.2%
  • Unhealthy for Sensitive Groups: 3.2%
  • Unhealthy or worse: 0.5%

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QUICK ANSWER

How is the air in Tacoma in August?

Good on a typical day: median AQI 47 across 2019–2025, with 3.7% of August days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 58.1% of August days were Good (AQI 0–50), 38.2% Moderate (51–100).
  • 8 days of 217 reached AQI 101+; the August peak was 175.
  • Best August: 2025; worst August: 2023.

Frequently asked questions

What is the air quality like in Tacoma in August?

Across 2019–2025, the median daily AQI in Tacoma in August was 47 (Good). 58.1% of days were Good, 38.2% Moderate, and 3.7% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is August a good time for outdoor exercise in Tacoma?

A typical August day in Tacoma sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 27 of August days (3.7%) reached AQI 101+ in 2019–2025.

Which pollutant causes Tacoma's August air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 66.4% of August days in Tacoma. The highest August AQI recorded in 2019–2025 was 175 (Unhealthy), in 2023.

Tacoma August air quality, year by year

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

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193146087PM2.5
202031441103PM2.5
202131462148PM2.5
202231481108O3
2023worst31524175O3
20243148090PM2.5
2025cleanest3144090PM2.5

What August air means in Tacoma

A typical August day in Tacoma sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 27 of August days (3.7%) reached AQI 101+ in 2019–2025.

August's median AQI of 47 is in line with Tacoma's whole-year median of 49, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Tacoma runs in line with the national August norm; 3.7% of its August days topped AQI 100 versus 3.5% nationally (about the same).

August is part of Tacoma's summer season (June, July, August); the summer 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.