San Francisco Air Quality in July
Across 2019–2025, San Francisco's July air quality had a median AQI of 53 (Moderate) over 195 monitored days in the San Francisco-Oakland-Hayward, CA area. 4.1% of July days (8 of 195) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 72.3% of days. The cleanest July on record here was 2022 (median AQI 43, 0 days above 100) and the worst was 2023 (median 59, 5 days above 100, peak AQI 105).
- Good: 42.6%
- Moderate: 53.3%
- Unhealthy for Sensitive Groups: 4.1%
- Unhealthy or worse: 0.0%
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How is the air in San Francisco in July?
Moderate on a typical day: median AQI 53 across 2019–2025, with 4.1% of July days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓42.6% of July days were Good (AQI 0–50), 53.3% Moderate (51–100).
- ✓8 days of 195 reached AQI 101+; the July peak was 115.
- ✓Best July: 2022; worst July: 2023.
Frequently asked questions
What is the air quality like in San Francisco in July?▾
Across 2019–2025, the median daily AQI in San Francisco in July was 53 (Moderate). 42.6% of days were Good, 53.3% Moderate, and 4.1% reached Unhealthy for Sensitive Groups or worse, based on 195 monitored days in EPA's Air Quality System.
Is July a good time for outdoor exercise in San Francisco?▾
A typical July day in San Francisco is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 24 of July days (4.1%) 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 Francisco's July air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 72.3% of July days in San Francisco. The highest July AQI recorded in 2019–2025 was 115 (Unhealthy for Sensitive Groups), in 2023.
San Francisco July air quality, year by year
San Francisco July air quality by year (San Francisco-Oakland-Hayward, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 54 | 2 | 105 | PM2.5 |
| 2020 | 31 | 53 | 1 | 115 | PM2.5 |
| 2021 | 31 | 53 | 0 | 77 | PM2.5 |
| 2022cleanest | 31 | 43 | 0 | 81 | PM2.5 |
| 2023worst | 31 | 59 | 5 | 105 | PM2.5 |
| 2024 | 31 | 55 | 0 | 98 | PM2.5 |
| 2025 | 9 | 13 | 0 | 47 | PM2.5 |
What July air means in San Francisco
A typical July day in San Francisco is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 24 of July days (4.1%) 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 53 is in line with San Francisco's whole-year median of 53, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so San Francisco runs above the national July norm; 4.1% of its July days topped AQI 100 versus 3.6% nationally (about the same).
July is part of San Francisco's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Francisco
The latest EPA AirNow observation puts San Francisco's AQI at 36 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current San Francisco air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Francisco-Oakland-Hayward, 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.