Metro area air quality · 2025
San Diego-Carlsbad, CA
Median AQI 67 (Moderate). 17.5% of monitored days rated Good across this metro's EPA monitoring network.
- 67
- Median AQI
- 17.5%
- Good-air days
- 7
- Unhealthy days
- 1%
- Cleaner than US metros
San Diego-Carlsbad, CA posted a 2025 median AQI of 67 (Moderate) with 17.5% Good days
According to the U.S. EPA Air Quality System, the San Diego-Carlsbad, CA CBSA recorded a median AQI of 67 across 365 monitored days in 2025, with 17.5% rated Good and 7 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The San Diego-Carlsbad, CA CBSA's 17.5% Good-day share places it cleaner than 1% of US metros in 2025.
- Closest median-AQI peer
- Bakersfield, CA (17.5% Good, median AQI 70) is the closest nationwide median-AQI peer to San Diego-Carlsbad, CA.
- 2020–2025 Good-day shift
- San Diego-Carlsbad, CA's Good-day share moved +8.9 points from 2020 to 2025 (median AQI -7).
- Median AQI
- Median AQI: 67
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
San Diego-Carlsbad, CA lands in the lower Good-day tercile (17.5% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs moderate, among the more polluted US metros, with a median AQI of 67 and 17.5% of 365 monitored days in the Good band.
- 67
- median AQI · Moderate
- 17.5%
- days rated Good
- 1%
- cleaner than US metros
- 161
- worst single reading
7 days reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- San Diego-Carlsbad, CA metro's Good-day share rose from 14.8% to 18.9% between the 2024 and 2025 EPA annual releases, a change of +4.1 percentage points.
- San Diego-Carlsbad, CA metro's Unhealthy-category days rose from 4 to 7 between the 2024 and 2025 EPA annual releases, a change of +3 days.
- San Diego-Carlsbad, CA metro's median AQI fell from 71 to 67 between the 2024 and 2025 EPA annual releases, a change of -4 points.
San Diego-Carlsbad, CA lands in the lower Good-day tercile (17.5% Good), a thinner clean-air share than most CBSA peers here. Signature read: 17.5% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 67 over 365 measured days in 2025 (Moderate / Very Poor). The monitored-day split lands at 64 Good (18%), 268 Moderate (73%), and 26 Unhealthy-for-Sensitive-Groups (7%). The 90th-percentile AQI finished at 100; the highest single-day reading hit 161 (Unhealthy).
Across 2020–2025, Good-day share shifted +8.9 points and median AQI moved -7 (improving). The annual record contains 7 days at Unhealthy or worse. Metros with comparable AQI profiles include Bakersfield, CA (17.5% good, AQI 70); El Centro, CA (27.7% good, AQI 64); El Paso, TX (18.1% good, AQI 70).
Air Quality Summary
Median AQI
67
Moderate
Good Days
17.5%
64 of 365 days
Max AQI
161
Unhealthy
Health Grade
Very Poor
90th pct: 100
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
64
18%
Moderate
268
73%
USG
26
7%
Unhealthy
7
2%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The San Diego-Carlsbad, CA metro area's air quality is rated Very Poor based on 17.5% good air days. There were 7 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 26 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 161. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the San Diego-Carlsbad, CA metro compare?
How San Diego-Carlsbad, CA compares
5-Year Air Quality Trend
Air quality is improving in the San Diego-Carlsbad, CA metro. Highest Good-day share: 2023 (19.0%, 61 of 321 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 33 | 284 | 14 | 74 | 192 |
| 2021 | 52 | 297 | 0 | 67 | 133 |
| 2022 | 42 | 297 | 1 | 63 | 156 |
| 2023 | 61 | 260 | 0 | 67 | 150 |
| 2024 | 47 | 267 | 4 | 71 | 161 |
| 2025 | 64 | 268 | 7 | 67 | 161 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near San Diego-Carlsbad, CA (67).
Bakersfield, CA
Median AQI 70 · 17.5% Good-day share
El Centro, CA
Median AQI 64 · 27.7% Good-day share
El Paso, TX
Median AQI 70 · 18.1% Good-day share
Visalia-Porterville, CA
Median AQI 64 · 24.1% Good-day share
Houston-The Woodlands-Sugar Land, TX
Median AQI 63 · 10.1% Good-day share
Albuquerque, NM
Median AQI 61 · 24.9% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to San Diego-Carlsbad, CA's 7 (independent of median AQI).
Fargo, ND-MN
7 unhealthy-or-worse days · median AQI 37
Green Bay, WI
7 unhealthy-or-worse days · median AQI 38
Appleton, WI
6 unhealthy-or-worse days · median AQI 38
Brainerd, MN
8 unhealthy-or-worse days · median AQI 39
Chicago-Naperville-Elgin, IL-IN-WI
6 unhealthy-or-worse days · median AQI 56
Marquette, MI
6 unhealthy-or-worse days · median AQI 19
Frequently Asked Questions
How many unhealthy air days does San Diego-Carlsbad, CA have? ▼
What is the air quality in the San Diego-Carlsbad, CA metro area? ▼
Is air quality in San Diego-Carlsbad, CA getting better or worse? ▼
What does AQI 67 mean for health? ▼
How does San Diego-Carlsbad, CA compare to other metro areas? ▼
What is the 90th percentile AQI for San Diego-Carlsbad, CA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for San Diego-Carlsbad, 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 Diego-Carlsbad, CA · 2020–2025