San Francisco vs Seattle Air Quality Comparison
Which city has cleaner air right now, from the latest EPA AirNow AQI
As of September 23, 2026, Seattle, WA has cleaner air than San Francisco, CA — AQI 34 (Good) vs 57 (Moderate), a gap of 23 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. San Francisco's reading is driven by PM2.5 and Seattle's by PM2.5.
San Francisco, CA
Moderate
Seattle, WA
Good
Summary
Seattle has 23 points better air quality
Seattle has an AQI of 34 compared to 57
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5-Day Forecast Comparison
| Day | San Francisco | Seattle | Better |
|---|---|---|---|
| Today | AQI 53 | AQI 39 | Seattle |
| Wed, Sep 23 | AQI 55 | AQI 28 | Seattle |