San Jose Air Quality in July
Across 2019–2025, San Jose's July air quality had a median AQI of 51 (Moderate) over 217 monitored days in the San Jose-Sunnyvale-Santa Clara, CA area. 2.3% of July days (5 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 53.0% of days. The cleanest July on record here was 2025 (median AQI 37, 0 days above 100) and the worst was 2024 (median 58, 2 days above 100, peak AQI 111).
- Good: 49.8%
- Moderate: 47.9%
- Unhealthy for Sensitive Groups: 2.3%
- Unhealthy or worse: 0.0%
Extra Protection for San Jose Homes
Air quality in San Jose is moderate (AQI 53), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How is the air in San Jose in July?
Moderate on a typical day: median AQI 51 across 2019–2025, with 2.3% of July days above AQI 100. Ground-level ozone is the main driver.
- ✓49.8% of July days were Good (AQI 0–50), 47.9% Moderate (51–100).
- ✓5 days of 217 reached AQI 101+; the July peak was 126.
- ✓Best July: 2025; worst July: 2024.
Frequently asked questions
What is the air quality like in San Jose in July?▾
Across 2019–2025, the median daily AQI in San Jose in July was 51 (Moderate). 49.8% of days were Good, 47.9% Moderate, and 2.3% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is July a good time for outdoor exercise in San Jose?▾
A typical July day in San Jose is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 43 of July days (2.3%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes San Jose's July air quality problems?▾
Ground-level ozone set the daily AQI on 53.0% of July days in San Jose. The highest July AQI recorded in 2019–2025 was 126 (Unhealthy for Sensitive Groups), in 2024.
San Jose July air quality, year by year
San Jose July air quality by year (San Jose-Sunnyvale-Santa Clara, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 52 | 1 | 126 | PM2.5 |
| 2020 | 31 | 48 | 0 | 86 | PM2.5 |
| 2021 | 31 | 53 | 0 | 87 | PM2.5 |
| 2022 | 31 | 46 | 0 | 74 | O3 |
| 2023 | 31 | 56 | 2 | 112 | O3 |
| 2024worst | 31 | 58 | 2 | 111 | PM2.5 |
| 2025cleanest | 31 | 37 | 0 | 64 | O3 |
What July air means in San Jose
A typical July day in San Jose is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 43 of July days (2.3%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
July's median AQI of 51 is in line with San Jose's whole-year median of 50, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so San Jose runs above the national July norm; 2.3% of its July days topped AQI 100 versus 3.6% nationally (below average).
July is part of San Jose's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Jose
The latest EPA AirNow observation puts San Jose's AQI at 53 (PM2.5). The figures above are multi-year month 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.