Metro area air quality · 2025
San Francisco-Oakland-Hayward, CA
Median AQI 21 (Good). 91.6% of monitored days rated Good across this metro's EPA monitoring network.
- 21
- Median AQI
- 91.6%
- Good-air days
- 0
- Unhealthy days
San Francisco-Oakland-Hayward, CA posted a 2025 median AQI of 21 (Good) with 91.6% Good days
According to the U.S. EPA Air Quality System, the San Francisco-Oakland-Hayward, CA CBSA recorded a median AQI of 21 across 95 monitored days in 2025, with 91.6% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Closest median-AQI peer
- Kahului-Wailuku-Lahaina, HI (98.1% Good, median AQI 21) is the closest nationwide median-AQI peer to San Francisco-Oakland-Hayward, CA.
- 2020–2025 Good-day shift
- San Francisco-Oakland-Hayward, CA's Good-day share moved +49.4 points from 2020 to 2025 (median AQI -32).
- Median AQI
- Median AQI: 21
- Good days
- Good days: 91.6%
Aggregated from EPA Air Quality System (2025), 95 monitored days. EPA AQS →
The verdict
San Francisco-Oakland-Hayward, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (91.6% of 95 monitored days). On the EPA scale the metro runs good, with a median AQI of 21 and 91.6% of 95 monitored days in the Good band.
- 21
- median AQI · Good
- 91.6%
- days rated Good
- 66
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2024 EPA annual release
- San Francisco-Oakland-Hayward, CA metro's Good-day share rose from 36.6% to 40.8% between the 2023 and 2024 EPA annual releases, a change of +4.2 percentage points.
- San Francisco-Oakland-Hayward, CA metro's peak single-day AQI fell from 130 to 105 between the 2023 and 2024 EPA annual releases, a change of -25 points.
San Francisco-Oakland-Hayward, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (91.6% of 95 monitored days). Signature read: 91.6% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 21 over 95 measured days in 2025 (Good / Excellent). The monitored-day split lands at 87 Good (92%), 8 Moderate (8%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 49; the highest single-day reading hit 66 (Moderate).
Across 2020–2025, Good-day share shifted +49.4 points and median AQI moved -32 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Kahului-Wailuku-Lahaina, HI (98.1% good, AQI 21); Othello, WA (90.5% good, AQI 21); Palatka, FL (95.6% good, AQI 21).
Air Quality Summary
Median AQI
21
Good
Good Days
91.6%
87 of 95 days
Max AQI
66
Moderate
Health Grade
Excellent
90th pct: 49
AQI Day Breakdown (2025)
Distribution of 95 monitored days across EPA AQI categories.
Good
87
92%
Moderate
8
8%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The San Francisco-Oakland-Hayward, CA metro area's air quality is rated Excellent based on 91.6% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the San Francisco-Oakland-Hayward, CA metro compare?
How San Francisco-Oakland-Hayward, CA compares
5-Year Air Quality Trend
Air quality is stable in the San Francisco-Oakland-Hayward, CA metro. Highest Good-day share: 2020 (42.1%, 150 of 356 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 150 | 194 | 12 | 53 | 243 |
| 2021 | 139 | 216 | 1 | 54 | 151 |
| 2022 | 143 | 217 | 0 | 53 | 129 |
| 2023 | 129 | 223 | 0 | 54 | 130 |
| 2024 | 149 | 216 | 0 | 53 | 105 |
| 2025 | 87 | 8 | 0 | 21 | 66 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near San Francisco-Oakland-Hayward, CA (21).
Kahului-Wailuku-Lahaina, HI
Median AQI 21 · 98.1% Good-day share
Othello, WA
Median AQI 21 · 90.5% Good-day share
Palatka, FL
Median AQI 21 · 95.6% Good-day share
Aberdeen, WA
Median AQI 22 · 97.3% Good-day share
Bremerton-Silverdale, WA
Median AQI 22 · 95.5% Good-day share
Centralia, WA
Median AQI 20 · 91.3% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to San Francisco-Oakland-Hayward, CA's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Albany-Schenectady-Troy, NY
0 unhealthy-or-worse days · median AQI 41
Frequently Asked Questions
How many unhealthy air days does San Francisco-Oakland-Hayward, CA have? ▼
What is the air quality in the San Francisco-Oakland-Hayward, CA metro area? ▼
Is air quality in San Francisco-Oakland-Hayward, CA getting better or worse? ▼
What does AQI 21 mean for health? ▼
How does San Francisco-Oakland-Hayward, CA compare to other metro areas? ▼
What is the 90th percentile AQI for San Francisco-Oakland-Hayward, CA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for San Francisco-Oakland-Hayward, CA, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, San Francisco-Oakland-Hayward, CA · 2020–2025