Outdoor
Outdoor activity is generally possible, but conditions are not ideal.
Why: AQI or pollutant levels are elevated, so this guidance is more cautious.
San Jose, California, United States
San Jose air quality today
Outdoor activity is generally possible, but conditions are not ideal.
Data: Hourly Open-Meteo model estimateThe latest update is older than expected, so this page is showing an estimate for the current hour.Detailed metrics and guidance use the latest available detailed data.
Practical guidance
Running
Outdoor running is generally fine. If you are sensitive to air pollution, consider keeping the effort easy.
Why: Air quality indicators are elevated, so the running guidance is more cautious.
Ventilation
Consider waiting before longer ventilation.
Why: PM2.5, PM10, NO2 or ozone is elevated, so longer ventilation may bring more outdoor pollution indoors.
Air quality and outdoor metrics
US AQI
Air Quality Index
61
Moderate
PM2.5
Fine particulate matter
23.1µg/m³
Elevated
PM10
Coarse particulate matter
24.9µg/m³
Moderate
NO₂
Nitrogen dioxide
27µg/m³
Low
O₃
Ozone
30µg/m³
Low
UV index
Sun exposure level
0
Low
Temperature
Air temperature
15°C
Comfortable
Feels like
Apparent temperature
15°C
Comfortable
Wind
Wind speed
1km/h
Light
Humidity
Relative humidity
77%
Humid
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Disclaimer
This information is a general estimate only and is not medical advice.
Location
San Jose, United States
Coordinates: 37.3382, -121.8863 · America/Los_Angeles
Interpret AQI for outdoor activity
Calculic's European AQI calculator assesses the value using your population group and planned activity intensity.
Interpret AQI in CalculicThis page's European AQI value, city and timestamp are passed to the calculator through the link.
What affects air quality in San Jose
The Bay Area Air District's 2026 network plan describes how northwesterly winds can bring ozone and its precursors into the Santa Clara Valley around San Jose - Jackson, while light winds and winter inversions can increase particle concentrations.
This is the plan's site-area meteorological context, not a forecast, a source ranking or a claim that all San Jose neighborhoods have the same conditions.
Local monitoring and context
The Bay Area Air District's 2026 network plan identifies San Jose - Jackson as an NCore site and lists ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide and particulate monitoring there.
This describes the documented station and selected pollutant coverage, not citywide readings or the provider of this page's current data.
City air quality FAQ
How should I read the AQI for San Jose?
US AQI condenses air quality into one value. On this page, it helps you quickly judge whether conditions look good, moderate or more polluted than usual.
Is the air quality good for going outside?
Check the outdoor and running cards first. They combine AQI, particles, ozone, weather and other factors that can affect outdoor comfort.
Should I ventilate right now?
The ventilation card considers AQI and pollutants such as particles, nitrogen dioxide and ozone. If values are elevated, a shorter opening or a later moment may be better.
Why can air quality change during the day?
Weather, emissions, ozone formation, particles and air flow can shift local conditions, so the next hours can differ from the current reading.
Sources and methodology
Current data
This page uses US AQI.
Current and hourly air-quality values are CAMS-based model estimates, not measurements from a local monitoring station. They may not reflect street-level conditions.
- Displayed state
- This hour's model estimate
- Data time
- 30 Oct 2026, 09:00 am
- Weather data
- Open-Meteo
- Air-quality model data
- Copernicus Atmosphere Monitoring Service (CAMS). Open-Meteo selects data suited to this location. Possible CAMS datasets: CAMS European air quality forecasts, ENSEMBLE data; CAMS global atmospheric composition forecasts.
- Licence
- CC BY 4.0
City Air Quality selects the active data package, combines weather and air-quality data, chooses the current or latest usable model value, and formats it for this page.
The latest update is older than expected, so this page is showing an estimate for the current hour.
Detailed metrics and guidance use the latest available detailed data.
Evergreen city statements
Each local statement is linked to a checked primary-authority source. A source check is editorial provenance and does not describe current-data freshness.
Local sources support the background claims below; they are not the source of the current data shown above unless explicitly stated otherwise.
Authoritative sources for local statements
2026 Annual Air Monitoring Network Plan — San Jose - Jackson, Tables 4.45–4.46
Bay Area Air District
- Scope
- San Jose
- Source checked
- 31 Aug 2026
Printed pages 98–99 identify Jackson as an NCore site, describe ozone transport and winter inversions, and list agency-operated ozone, CO, NO2, SO2 and particulate monitors. The discontinued NOy and NATTS programs are not claimed as active.
Applicability: Official local or regional background only; not current conditions, citywide uniformity, regulatory attainment or this site's current-data provenance.
Based on this source: The Bay Area Air District's 2026 network plan describes how northwesterly winds can bring ozone and its precursors into the Santa Clara Valley around San Jose - Jackson, while light winds and winter inversions can increase particle concentrations.
The Bay Area Air District's 2026 network plan identifies San Jose - Jackson as an NCore site and lists ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide and particulate monitoring there.