Metro area air quality · 2025

Urban Honolulu, HI

Median AQI 29 (Good). 97.3% of monitored days rated Good across this metro's EPA monitoring network.

29
Median AQI
97.3%
Good-air days
0
Unhealthy days
97%
Cleaner than US metros

Urban Honolulu, HI posted a 2025 median AQI of 29 (Good) with 97.3% Good days

According to the U.S. EPA Air Quality System, the Urban Honolulu, HI CBSA recorded a median AQI of 29 across 365 monitored days in 2025, with 97.3% 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 Urban Honolulu, HI CBSA's 97.3% Good-day share places it cleaner than 97% of US metros in 2025.
Closest median-AQI peer
Port Angeles, WA (85.5% Good, median AQI 29) is the closest nationwide median-AQI peer to Urban Honolulu, HI.
2020–2025 Good-day shift
Urban Honolulu, HI's Good-day share moved -1.9 points from 2020 to 2025 (median AQI +1).
Median AQI
Median AQI: 29

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Urban Honolulu, HI sits in the upper Good-day tercile among EPA CBSA metros on this site (97.3% of 365 monitored days). On the EPA scale the metro runs good, among the cleanest 10% of US metros, with a median AQI of 29 and 97.3% of 365 monitored days in the Good band.

29
median AQI · Good
97.3%
days rated Good
97%
cleaner than US metros
59
worst single reading

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

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Urban Honolulu, HI metro's peak single-day AQI fell from 85 to 59 between the 2024 and 2025 EPA annual releases, a change of -26 points.
  • Urban Honolulu, HI metro's Good-day share fell from 98.4% to 97.3% between the 2024 and 2025 EPA annual releases, a change of -1.1 percentage points.

Compared against 366 monitored days in 2024 and 365 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Urban Honolulu, HI sits in the upper Good-day tercile among EPA CBSA metros on this site (97.3% of 365 monitored days). Signature read: 97.3% 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 29 over 365 measured days in 2025 (Good / Excellent). The monitored-day split lands at 355 Good (97%), 10 Moderate (3%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 39; the highest single-day reading hit 59 (Moderate).

Across 2020–2025, Good-day share shifted -1.9 points and median AQI moved +1 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Port Angeles, WA (85.5% good, AQI 29); Butte-Silver Bow, MT (84.9% good, AQI 28); Cookeville, TN (90.0% good, AQI 30).

Best and worst city air quality →

Air Quality Summary

Median AQI

29

Good

Good Days

97.3%

355 of 365 days

Max AQI

59

Moderate

Health Grade

Excellent

90th pct: 39

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

355

97%

Moderate

10

3%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Urban Honolulu, HI metro area's air quality is rated Excellent based on 97.3% 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 Urban Honolulu, HI metro compare?

How Urban Honolulu, HI compares

Good-day share better than typical
Urban Honolulu, HI 97.3%
Port Angeles, WA 85.5%
Typical US metro 70.6%
Median AQI better than typical
Urban Honolulu, HI 29
Port Angeles, WA 29
Typical US metro 41
Unhealthy days / yr better than typical
Urban Honolulu, HI 0
Port Angeles, WA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Urban Honolulu, HI metro. Highest Good-day share: 2021 (99.7%, 364 of 365 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 363 3 0 28
2021 364 1 0 28
2022 356 9 0 29
2023 337 27 0 31
2024 360 6 0 31
2025 355 10 0 29

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Urban Honolulu, HI (29).

Port Angeles, WA

Median AQI 29 · 85.5% Good-day share

29

Butte-Silver Bow, MT

Median AQI 28 · 84.9% Good-day share

28

Cookeville, TN

Median AQI 30 · 90.0% Good-day share

30

Dodge City, KS

Median AQI 28 · 89.8% Good-day share

28

Lynchburg, VA

Median AQI 30 · 85.2% Good-day share

30

Moses Lake, WA

Median AQI 28 · 79.7% Good-day share

28

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Urban Honolulu, HI'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 Urban Honolulu, HI have? ▼
In 2025, the Urban Honolulu, HI metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 59.
What is the air quality in the Urban Honolulu, HI metro area? ▼
The Urban Honolulu, HI metro area has a median Air Quality Index (AQI) of 29, rated "Good." 97.3% of monitored days (355 out of 365) had good air quality in 2025.
Is air quality in Urban Honolulu, HI getting better or worse? ▼
Air quality in the Urban Honolulu, HI 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: 2021 at 99.7% (364 of 365 days). Lowest qualifying Good-day share: 2023 at 92.6% (337 of 364 days).
What does AQI 29 mean for health? ▼
An AQI of 29 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 Urban Honolulu, HI compare to other metro areas? ▼
The Urban Honolulu, HI metro has 97.3% good air days. Similar metros: Port Angeles, WA (85.5% good), Butte-Silver Bow, MT (84.9% good), Cookeville, TN (90.0% good).
What is the 90th percentile AQI for Urban Honolulu, HI? ▼
The 90th percentile AQI for the Urban Honolulu, HI metro area is 39, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 59 (Moderate).

Data Sources

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