San Diego Air Quality in April
Across 2019–2025, San Diego's April air quality had a median AQI of 67 (Moderate) over 210 monitored days in the San Diego-Carlsbad, CA area. 7.1% of April days (15 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 60.5% of days. The cleanest April on record here was 2025 (median AQI 60, 1 day above 100) and the worst was 2022 (median 67, 4 days above 100, peak AQI 129).
- Good: 16.7%
- Moderate: 76.2%
- Unhealthy for Sensitive Groups: 7.1%
- Unhealthy or worse: 0.0%
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 April?
Moderate on a typical day: median AQI 67 across 2019–2025, with 7.1% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓16.7% of April days were Good (AQI 0–50), 76.2% Moderate (51–100).
- ✓15 days of 210 reached AQI 101+; the April peak was 133.
- ✓Best April: 2025; worst April: 2022.
Frequently asked questions
What is the air quality like in San Diego in April?▾
Across 2019–2025, the median daily AQI in San Diego in April was 67 (Moderate). 16.7% of days were Good, 76.2% Moderate, and 7.1% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in San Diego?▾
A typical April day in San Diego is Moderate (median AQI 67): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of April days (7.1%) 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 April air quality problems?▾
Ground-level ozone set the daily AQI on 60.5% of April days in San Diego. The highest April AQI recorded in 2019–2025 was 133 (Unhealthy for Sensitive Groups), in 2022.
San Diego April air quality, year by year
San Diego April 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 | 30 | 68 | 2 | 105 | PM2.5 |
| 2020 | 30 | 64 | 2 | 105 | O3 |
| 2021 | 30 | 68 | 1 | 119 | O3 |
| 2022worst | 30 | 67 | 4 | 129 | O3 |
| 2023 | 30 | 76 | 3 | 133 | O3 |
| 2024 | 30 | 65 | 2 | 112 | O3 |
| 2025cleanest | 30 | 60 | 1 | 126 | O3 |
What April air means in San Diego
A typical April day in San Diego is Moderate (median AQI 67): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of April days (7.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
April's median AQI of 67 is in line with San Diego's whole-year median of 67, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so San Diego runs above the national April norm; 7.1% of its April days topped AQI 100 versus 0.7% nationally (above average).
April is part of San Diego's spring season (March, April, May); the spring page pools all three months.
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 month 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.