San Diego Air Quality in Summer
Across 2019–2025, San Diego's summer (June–August) air quality had a median AQI of 76 (Moderate) over 644 monitored days in the San Diego-Carlsbad, CA area. 18.1% of summer days (116 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 71.3% of days. The cleanest summer on record here was 2020 (median AQI 70, 7 days above 100) and the worst was 2023 (median 84, 29 days above 100, peak AQI 150).
- Good: 5.1%
- Moderate: 76.9%
- Unhealthy for Sensitive Groups: 16.5%
- Unhealthy or worse: 1.6%
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 summer?
Moderate on a typical day: median AQI 76 across 2019–2025, with 18.1% of summer days above AQI 100. Ground-level ozone is the main driver.
- ✓5.1% of summer days were Good (AQI 0–50), 76.9% Moderate (51–100).
- ✓116 days of 644 reached AQI 101+; the summer peak was 169.
- ✓Cleanest month: June; worst month: July.
Frequently asked questions
What is the air quality like in San Diego in summer?▾
Across 2019–2025, the median daily AQI in San Diego in summer was 76 (Moderate). 5.1% of days were Good, 76.9% Moderate, and 18.1% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in San Diego?▾
A typical summer day in San Diego is Moderate (median AQI 76): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 6 of summer days (18.1%) 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 summer air quality problems?▾
Ground-level ozone set the daily AQI on 71.3% of summer days in San Diego. The highest summer AQI recorded in 2019–2025 was 169 (Unhealthy), in 2023.
San Diego summer air quality, year by year
San Diego summer 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 | 74 | 14 | 169 | O3 |
| 2020cleanest | 92 | 70 | 7 | 154 | PM2.5 |
| 2021 | 92 | 71 | 11 | 126 | O3 |
| 2022 | 92 | 67 | 13 | 143 | O3 |
| 2023worst | 92 | 84 | 29 | 150 | O3 |
| 2024 | 92 | 84 | 23 | 159 | O3 |
| 2025 | 92 | 76 | 19 | 161 | O3 |
What summer air means in San Diego
A typical summer day in San Diego is Moderate (median AQI 76): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 6 of summer days (18.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Summer's median AQI of 76 is above San Diego's whole-year median of 67, making it one of the area's dirtier periods. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so San Diego runs above the national Summer norm; 18.1% of its Summer days topped AQI 100 versus 3.6% nationally (above average).
Within the season, June is the cleanest month (median AQI 71, 15.8% of days above 100) and July the worst (median 76, 21.2% 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.