San Jose Air Quality in 2023
In 2023, San Jose's air quality (San Jose-Sunnyvale-Santa Clara, CA area) had a median daily AQI of 45 (Good) across 365 monitored days. 4 days (1.1%) reached Unhealthy for Sensitive Groups or worse, 226 were Good, and the year's peak AQI was 134 (Unhealthy for Sensitive Groups). Ground-level ozone set the daily AQI on 213 of those days. The cleanest month of 2023 was January (median AQI 39, 0 days above 100) and the worst was July (median 56, 2 days above 100, peak 112).
- Good: 61.9%
- Moderate: 37.0%
- Unhealthy for Sensitive Groups: 1.1%
- Unhealthy or worse: 0.0%
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How was San Jose's air quality in 2023?
Good on a typical day: median AQI 45, with 4 days above AQI 100 out of 365 monitored — the 3rd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2023: 134 (Unhealthy for Sensitive Groups).
- ✓Ground-level ozone was the main pollutant on 213 days.
- ✓Cleanest month: January; worst: July.
Frequently asked questions
What was the average AQI in San Jose in 2023?▾
EPA's Air Quality System puts San Jose's (San Jose-Sunnyvale-Santa Clara, CA) median daily AQI for 2023 at 45, which is Good. 4 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 134.
Which month had the worst air quality in San Jose in 2023?▾
The cleanest month of 2023 was January (median AQI 39, 0 days above 100) and the worst was July (median 56, 2 days above 100, peak 112).
Was 2023 a good or bad year for San Jose's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 3rd cleanest by days above AQI 100. 2023's median of 45 is below the area's typical annual median of 50.
San Jose month by month in 2023
San Jose air quality month by month, 2023 (San Jose-Sunnyvale-Santa Clara, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| Januarycleanest | 31 | 39 | 0 | 83 | O3 |
| February | 28 | 45 | 0 | 62 | PM2.5 |
| March | 31 | 42 | 0 | 59 | O3 |
| April | 30 | 45 | 0 | 71 | O3 |
| May | 31 | 39 | 0 | 81 | O3 |
| June | 30 | 40 | 0 | 77 | O3 |
| Julyworst | 31 | 56 | 2 | 112 | O3 |
| August | 31 | 51 | 1 | 129 | O3 |
| September | 30 | 45 | 1 | 134 | O3 |
| October | 31 | 46 | 0 | 90 | O3 |
| November | 30 | 52 | 0 | 68 | PM2.5 |
| December | 31 | 57 | 0 | 88 | PM2.5 |
How 2023 compares
Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 3rd cleanest by days above AQI 100.
2023's median of 45 is below the area's typical annual median of 50.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Jose
The latest EPA AirNow observation puts San Jose's AQI at 44 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current San Jose air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Jose-Sunnyvale-Santa Clara, CA), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.