San Diego Air Quality in Spring
Across 2019–2025, San Diego's spring (March–May) air quality had a median AQI of 61 (Moderate) over 644 monitored days in the San Diego-Carlsbad, CA area. 4.7% of spring days (30 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 55.7% of days. The cleanest spring on record here was 2021 (median AQI 58, 1 day above 100) and the worst was 2022 (median 64, 7 days above 100, peak AQI 156).
- Good: 23.6%
- Moderate: 71.7%
- Unhealthy for Sensitive Groups: 4.2%
- Unhealthy or worse: 0.5%
Extra Protection for San Diego Homes
Air quality in San Diego is moderate (AQI 54), 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 Diego in spring?
Moderate on a typical day: median AQI 61 across 2019–2025, with 4.7% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓23.6% of spring days were Good (AQI 0–50), 71.7% Moderate (51–100).
- ✓30 days of 644 reached AQI 101+; the spring peak was 156.
- ✓Cleanest month: March; worst month: April.
Frequently asked questions
What is the air quality like in San Diego in spring?▾
Across 2019–2025, the median daily AQI in San Diego in spring was 61 (Moderate). 23.6% of days were Good, 71.7% Moderate, and 4.7% 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 Diego?▾
A typical spring day in San Diego is Moderate (median AQI 61): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 21 of spring days (4.7%) 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 Diego's spring air quality problems?▾
Ground-level ozone set the daily AQI on 55.7% of spring days in San Diego. The highest spring AQI recorded in 2019–2025 was 156 (Unhealthy), in 2022.
San Diego spring air quality, year by year
San Diego spring air quality by year (San Diego-Carlsbad, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 61 | 3 | 105 | PM2.5 |
| 2020 | 92 | 61 | 5 | 151 | PM2.5 |
| 2021cleanest | 92 | 58 | 1 | 119 | O3 |
| 2022worst | 92 | 64 | 7 | 156 | O3 |
| 2023 | 92 | 64 | 4 | 133 | O3 |
| 2024 | 92 | 59 | 4 | 119 | O3 |
| 2025 | 92 | 62 | 6 | 151 | O3 |
What spring air means in San Diego
A typical spring day in San Diego is Moderate (median AQI 61): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 21 of spring days (4.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Spring's median AQI of 61 is below San Diego's whole-year median of 67, 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 Diego runs above the national Spring norm; 4.7% of its Spring days topped AQI 100 versus 0.8% nationally (above average).
Within the season, March is the cleanest month (median AQI 53, 0.5% of days above 100) and April the worst (median 67, 7.1% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Diego
The latest EPA AirNow observation puts San Diego's AQI at 54 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current San Diego air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Diego-Carlsbad, 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.