Air quality
Air quality in Santa Clara, CA today
Updated
Moderate (US AQI 54) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Sun, Oct 25, 1:00 pm (20:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Santa Clara, California, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 54 Moderate
- PM2.5
- 5.7 µg/m³ 0.4× WHO 24-h guideline
- PM10
- 6.3 µg/m³
- Ozone
- 105 µg/m³
- Dominant pollutant
- PM2.5 sub-index 54
- Best hour today
- 1:00 pm AQI 54
- European AQI
- 45
Air quality in Santa Clara, CA right now
Right now the modelled US Air Quality Index for Santa Clara, California, United States is 54, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 54. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 5.7 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 6.3 µg/m³ against a guideline of 45; ozone is 105 µg/m³ (above the WHO 8-hour level of 100); nitrogen dioxide is 2.6 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 4.2, carbon monoxide 172 µg/m³.
Santa Clara, CA AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 54 around Sun 1:00 pm to 72 around Mon 10:00 am, staying "Moderate" throughout.
The following day looks similar, averaging about 63.
| Local time (America/Los_Angeles) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Sun 1:00 pm | 54 | Moderate | 5.7 | 6 | 105 |
| Sun 4:00 pm | 54 | Moderate | 6.9 | 8 | 103 |
| Sun 7:00 pm | 55 | Moderate | 13.4 | 16 | 56 |
| Sun 10:00 pm | 57 | Moderate | 28 | 30 | 23 |
| Mon 1:00 am | 60 | Moderate | 31.9 | 36 | 15 |
| Mon 4:00 am | 65 | Moderate | 37.6 | 43 | 15 |
| Mon 7:00 am | 69 | Moderate | 28 | 34 | 16 |
| Mon 10:00 am | 72 | Moderate | 13.7 | 18 | 58 |
| Mon 1:00 pm | 72 | Moderate | 7.9 | 11 | 83 |
| Mon 4:00 pm | 73 | Moderate | 6.4 | 10 | 83 |
| Mon 7:00 pm | 72 | Moderate | 4.7 | 7 | 68 |
| Mon 10:00 pm | 69 | Moderate | 6.2 | 8 | 51 |
| Tue 1:00 am | 64 | Moderate | 8 | 11 | 44 |
| Tue 4:00 am | 58 | Moderate | 11 | 15 | 46 |
| Tue 7:00 am | 52 | Moderate | 13.9 | 19 | 46 |
| Tue 10:00 am | 50 | Good | 13.6 | 19 | 66 |
| Tue 1:00 pm | 50 | Good | 10.4 | 15 | 83 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Santa Clara, CA today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 1:00 pm (AQI 54, Moderate) and the worst around 9:00 pm (AQI 56). The difference across the day is small, so timing matters little.
Santa Clara, CA vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 49 (Good). Santa Clara, CA at 54 is 5 points worse than average.
It ranks 391 of 619 from cleanest to most polluted; the cleanest is Casper (16) and the most polluted Springfield, PA (131).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Santa Clara, CA
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| San Jose | 6 km | 54 | Moderate | 5.7 |
| Sunnyvale | 7 km | 54 | Moderate | 5.7 |
| Newark, CA | 21 km | 57 | Moderate | 10.3 |
| Fremont | 22 km | 57 | Moderate | 10.3 |
| Union City | 27 km | 57 | Moderate | 10.3 |
| Hayward | 37 km | 57 | Moderate | 10.3 |
| Dublin, CA | 39 km | 57 | Moderate | 10.3 |
| Ashland | 40 km | 57 | Moderate | 10.3 |
Model vs measured
The nearest measured PM2.5 reading is 3.2 µg/m³ from Sensor.Community (median of 3 sensors), centred about 18 km from the city centre. That is close to the model estimate of 5.7 µg/m³. Low-cost sensors can read high in humid air; reference monitors are more accurate but sparser.
Wildfire smoke
PM2.5 is forecast to reach 38 µg/m³ in the next 24 hours while NASA satellites detected 24 fire hotspots within 300 km in the last day (nearest about 11 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.
Advice for sensitive groups
At 54, most people are fine outdoors. If you are unusually sensitive to PM2.5, keep long or intense workouts to the cleaner hours shown above.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Santa Clara
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), Sensor.Community, NASA FIRMS.