San Diego Air Quality in July
Across 2019–2025, San Diego's July air quality had a median AQI of 76 (Moderate) over 217 monitored days in the San Diego-Carlsbad, CA area. 21.2% of July days (46 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 73.7% of days. The cleanest July on record here was 2021 (median AQI 69, 1 day above 100) and the worst was 2023 (median 101, 19 days above 100, peak AQI 140).
- Good: 3.7%
- Moderate: 75.1%
- Unhealthy for Sensitive Groups: 19.8%
- Unhealthy or worse: 1.4%
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 July?
Moderate on a typical day: median AQI 76 across 2019–2025, with 21.2% of July days above AQI 100. Ground-level ozone is the main driver.
- ✓3.7% of July days were Good (AQI 0–50), 75.1% Moderate (51–100).
- ✓46 days of 217 reached AQI 101+; the July peak was 159.
- ✓Best July: 2021; worst July: 2023.
Frequently asked questions
What is the air quality like in San Diego in July?▾
Across 2019–2025, the median daily AQI in San Diego in July was 76 (Moderate). 3.7% of days were Good, 75.1% Moderate, and 21.2% 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 Diego?▾
A typical July 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 5 of July days (21.2%) 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 July air quality problems?▾
Ground-level ozone set the daily AQI on 73.7% of July days in San Diego. The highest July AQI recorded in 2019–2025 was 159 (Unhealthy), in 2023.
San Diego July air quality, year by year
San Diego July 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 | 31 | 84 | 7 | 159 | O3 |
| 2020 | 31 | 67 | 2 | 108 | PM2.5 |
| 2021cleanest | 31 | 69 | 1 | 115 | O3 |
| 2022 | 31 | 64 | 2 | 115 | O3 |
| 2023worst | 31 | 101 | 19 | 140 | O3 |
| 2024 | 31 | 90 | 11 | 159 | O3 |
| 2025 | 31 | 74 | 4 | 136 | O3 |
What July air means in San Diego
A typical July 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 5 of July days (21.2%) 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 76 is above San Diego's whole-year median of 67, making it one of the area's dirtier periods. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so San Diego runs above the national July norm; 21.2% of its July days topped AQI 100 versus 3.6% nationally (above average).
July is part of San Diego's summer season (June, July, August); the summer 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.