San Diego air quality
California, United States · Live AQI and hourly forecast for the next 5 days · updated Sat 5:00 PM local time
Moderate
Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.
- Next 24 hours
- 67–75US AQI, highest around Sun 12:00 PM
- Best time outside
- Sat 5:00 PM–8:00 PMUS AQI about 67
- PM2.5 vs WHO guideline
- 1.5×22 µg/m³ over 24 h, guideline 15
- Cigarette equivalent
- ≈ 1.0 a dayBerkeley Earth rule of thumb
- European AQI
- Moderatelevel 3 of 6
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Pollutants in San Diego right now
| Pollutant | Now | Next 24 h vs WHO | US AQI band |
|---|---|---|---|
| Fine particles (PM2.5) | 18 µg/m³ | 1.5× | Moderate |
| Coarse particles (PM10) | 24 µg/m³ | 0.6× | Good |
| Nitrogen dioxide (NO2) | 5.0 µg/m³ | 1.3× | Good |
| Ozone (O3) | 108 µg/m³ | 0.6× | Moderate |
| Sulphur dioxide (SO2) | 1.4 µg/m³ | 0.1× | Good |
| Carbon monoxide (CO) | 133 µg/m³ | 0.0× | Good |
| Desert dust | 1 µg/m³ | ||
| Smoke and haze (aerosol optical depth) | 0.09 | ||
| UV index | 0.8 |
“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM2.5, 45 for PM10, 25 for NO2, 40 for SO2 and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline.
Next 48 hours
Hourly US AQI. Highest 75 around Sun 12:00 PM, lowest 66 around Mon 4:00 PM.
5-day air quality forecast for San Diego
Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 150.
| Day | US AQI | At worst | PM2.5 avg | |
|---|---|---|---|---|
| Sat, Sep 26 | 65–70 | 20 | ||
| Sun, Sep 27 | 71–75 | 22 | ||
| Mon, Sep 28 | 62–75 | 15 | ||
| Tue, Sep 29 | 62–70 | 20 | ||
| Wed, Sep 30 | 71–76 | 22 |
Common questions about the air in San Diego
Is the air in San Diego safe today?
For most people, yes. Right now the US AQI in San Diego is 67, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.
When is the best time to be outside in San Diego?
Sat 5:00 PM–8:00 PM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 67. The worst hour is around Sun 12:00 PM, at 75.
What is the main pollutant in San Diego?
Fine particles (PM2.5). It drives the index right now, at 18 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.
How does San Diego's air compare with the WHO guideline?
1.5 times the guideline. Over the next 24 hours PM2.5 averages about 22 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO2 is also forecast above its guideline level.
How many cigarettes is a day of San Diego's air?
About 1.0 cigarette. Over the next 24 hours PM2.5 averages about 22 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in San Diego improve this week?
Today looks cleanest. Its AQI peaks at 70, against 76 on Wednesday, the worst day in the forecast.
Measured near San Diego
| Station | PM2.5 µg/m³ | Measured |
|---|---|---|
| San Diego - Sherman Elementary School AirNow, reference monitor | 9.8 | Sat 3:00 PM |
| Chula Vista AirNow, reference monitor | 9.5 | Sat 3:00 PM |
| San Diego - Kearny Villa Rd. AirNow, reference monitor | 12 | Sat 3:00 PM |
Air quality near San Diego
- Los Angeles 179 km NW
- Las Vegas 426 km NE
- Phoenix 481 km E
- Fresno 507 km NW
- San Francisco 738 km NW
- Sacramento 761 km NW
About this forecast
Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (10 km inside Europe), refreshed twice a day. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown; ground stations, where there are any nearby, show what monitors actually measure. The US AQI follows the US EPA scale and the European AQI the EEA bands. Readings for 32.72°N, 117.16°W, updated 2026-09-27 00:00 UTC.