Metro area air quality · 2025

Clearlake, CA

Median AQI 31 (Good). 99.2% of monitored days rated Good across this metro's EPA monitoring network.

31
Median AQI
99.2%
Good-air days
0
Unhealthy days
99%
Cleaner than US metros

Clearlake, CA posted a 2025 median AQI of 31 (Good) with 99.2% Good days

According to the U.S. EPA Air Quality System, the Clearlake, CA CBSA recorded a median AQI of 31 across 363 monitored days in 2025, with 99.2% rated Good and 0 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 Clearlake, CA CBSA's 99.2% Good-day share places it cleaner than 99% of US metros in 2025.
Closest median-AQI peer
Athens, OH (83.4% Good, median AQI 31) is the closest nationwide median-AQI peer to Clearlake, CA.
2020–2025 Good-day shift
Clearlake, CA's Good-day share moved +1.7 points from 2020 to 2025 (median AQI -1).
Median AQI
Median AQI: 31

Aggregated from EPA Air Quality System (2025), 363 monitored days. EPA AQS →

The verdict

Clearlake, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (99.2% of 363 monitored days). On the EPA scale the metro runs good, among the cleanest 10% of US metros, with a median AQI of 31 and 99.2% of 363 monitored days in the Good band.

31
median AQI · Good
99.2%
days rated Good
99%
cleaner than US metros
74
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Clearlake, CA sits in the upper Good-day tercile among EPA CBSA metros on this site (99.2% of 363 monitored days). Signature read: 99.2% 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 31 over 363 measured days in 2025 (Good / Excellent). The monitored-day split lands at 360 Good (99%), 3 Moderate (1%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 39; the highest single-day reading hit 74 (Moderate).

Across 2020–2025, Good-day share shifted +1.7 points and median AQI moved -1 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Athens, OH (83.4% good, AQI 31); Bellingham, WA (94.0% good, AQI 31); Coeur d'Alene, ID (77.8% good, AQI 31).

Best and worst city air quality →

Air Quality Summary

Median AQI

31

Good

Good Days

99.2%

360 of 363 days

Max AQI

74

Moderate

Health Grade

Excellent

90th pct: 39

AQI Day Breakdown (2025)

Distribution of 363 monitored days across EPA AQI categories.

Good

360

99%

Moderate

3

1%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Clearlake, CA metro area's air quality is rated Excellent based on 99.2% 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 Clearlake, CA metro compare?

How Clearlake, CA compares

Good-day share better than typical
Clearlake, CA 99.2%
Athens, OH 83.4%
Typical US metro 70.6%
Median AQI better than typical
Clearlake, CA 31
Athens, OH 31
Typical US metro 41
Unhealthy days / yr better than typical
Clearlake, CA 0
Athens, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Clearlake, CA metro. Highest Good-day share: 2024 (99.4%, 361 of 363 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 341 6 3 32
2021 348 7 1 33
2022 359 4 0 32
2023 357 6 0 32
2024 361 2 0 32
2025 360 3 0 31

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Clearlake, CA (31).

Athens, OH

Median AQI 31 · 83.4% Good-day share

31

Bellingham, WA

Median AQI 31 · 94.0% Good-day share

31

Coeur d'Alene, ID

Median AQI 31 · 77.8% Good-day share

31

Moscow, ID

Median AQI 31 · 83.4% Good-day share

31

Cookeville, TN

Median AQI 30 · 90.0% Good-day share

30

Crescent City, CA

Median AQI 32 · 81.8% Good-day share

32

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Clearlake, CA's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Frequently Asked Questions

How many unhealthy air days does Clearlake, CA have? ▼
In 2025, the Clearlake, CA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 74.
What is the air quality in the Clearlake, CA metro area? ▼
The Clearlake, CA metro area has a median Air Quality Index (AQI) of 31, rated "Good." 99.2% of monitored days (360 out of 363) had good air quality in 2025.
Is air quality in Clearlake, CA getting better or worse? ▼
Air quality in the Clearlake, CA metro is stable across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2024 at 99.4% (361 of 363 days). Lowest qualifying Good-day share: 2020 at 97.4% (341 of 350 days).
What does AQI 31 mean for health? ▼
An AQI of 31 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does Clearlake, CA compare to other metro areas? ▼
The Clearlake, CA metro has 99.2% good air days. Similar metros: Athens, OH (83.4% good), Bellingham, WA (94.0% good), Coeur d'Alene, ID (77.8% good).
What is the 90th percentile AQI for Clearlake, CA? ▼
The 90th percentile AQI for the Clearlake, CA metro area is 39, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 74 (Moderate).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Clearlake, 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, Clearlake, CA · 2020–2025