San Diego vs Modesto Air Quality Comparison
Which city has cleaner air right now, from the latest EPA AirNow AQI
As of September 23, 2026, Modesto, CA has cleaner air than San Diego, CA — AQI 52 (Moderate) vs 58 (Moderate), a gap of 6 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. San Diego's reading is driven by PM2.5 and Modesto's by PM2.5.
San Diego, CA
Moderate
Modesto, CA
Moderate
Summary
Modesto has 6 points better air quality
Modesto has an AQI of 52 compared to 58
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5-Day Forecast Comparison
| Day | San Diego | Modesto | Better |
|---|---|---|---|
| Today | AQI 55 | AQI 50 | Modesto |