San Jose Air Quality in Spring
Across 2019–2025, San Jose's spring (March–May) air quality had a median AQI of 44 (Good) over 644 monitored days in the San Jose-Sunnyvale-Santa Clara, CA area. 0.3% of spring days (2 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 62.3% of days. The cleanest spring on record here was 2020 (median AQI 40, 0 days above 100) and the worst was 2022 (median 46, 2 days above 100, peak AQI 112).
- Good: 70.8%
- Moderate: 28.9%
- Unhealthy for Sensitive Groups: 0.3%
- 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 spring?
Good on a typical day: median AQI 44 across 2019–2025, with 0.3% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓70.8% of spring days were Good (AQI 0–50), 28.9% Moderate (51–100).
- ✓2 days of 644 reached AQI 101+; the spring peak was 112.
- ✓Cleanest month: March; worst month: May.
Frequently asked questions
What is the air quality like in San Jose in spring?▾
Across 2019–2025, the median daily AQI in San Jose in spring was 44 (Good). 70.8% of days were Good, 28.9% Moderate, and 0.3% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in San Jose?▾
A typical spring day in San Jose sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Which pollutant causes San Jose's spring air quality problems?▾
Ground-level ozone set the daily AQI on 62.3% of spring days in San Jose. The highest spring AQI recorded in 2019–2025 was 112 (Unhealthy for Sensitive Groups), in 2022.
San Jose spring air quality, year by year
San Jose spring 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 | 92 | 44 | 0 | 65 | O3 |
| 2020cleanest | 92 | 40 | 0 | 84 | O3 |
| 2021 | 92 | 52 | 0 | 71 | PM2.5 |
| 2022worst | 92 | 46 | 2 | 112 | O3 |
| 2023 | 92 | 43 | 0 | 81 | O3 |
| 2024 | 92 | 43 | 0 | 67 | O3 |
| 2025 | 92 | 43 | 0 | 71 | O3 |
What spring air means in San Jose
A typical spring day in San Jose sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of spring days reached AQI 101+ in 2019–2025.
Spring's median AQI of 44 is below San Jose's whole-year median of 50, making it one of the area's cleaner periods. Nationally, the median Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so San Jose runs in line with the national Spring norm; 0.3% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, March is the cleanest month (median AQI 42, 0.0% of days above 100) and May the worst (median 47, 0.5% above 100).
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 season 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.