Metro area air quality · 2025

Cheyenne, WY

Median AQI 47 (Good). 69.8% of monitored days rated Good across this metro's EPA monitoring network.

47
Median AQI
69.8%
Good-air days
0
Unhealthy days
43%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 182 monitored days. EPA AQS →

The verdict

The Cheyenne, WY metro runs good on the EPA scale, more polluted than the median US metro, a median AQI of 47 with 69.8% of 182 monitored days in the Good band.

47
median AQI · Good
69.8%
days rated Good
43%
cleaner than US metros
108
worst single reading

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

Insights: Cheyenne, WY metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 47 over 182 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 127 Good days (70%), 54 Moderate (30%), and 1 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 67 while the highest single-day reading hit 108 (USG). Metro residents averaged roughly 20.9 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -186 and the median AQI moved +8 points, which classifies the multi-year trajectory as worsening. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Ardmore, OK (65.3% good, AQI 47); Baltimore-Columbia-Towson, MD (62.2% good, AQI 47); Boise City, ID (64.7% good, AQI 47).

Air Quality Summary

Median AQI

47

Good

Good Days

69.8%

127 of 182 days

Max AQI

108

USG

Health Grade

Moderate

90th pct: 67

AQI Day Breakdown (2025)

Distribution of 182 monitored days across EPA AQI categories.

Good

127

70%

Moderate

54

30%

USG

1

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Cheyenne, WY metro area's air quality is rated Moderate based on 69.8% 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 Cheyenne, WY metro compare?

How Cheyenne, WY compares

Good-day share worse than US avg
Cheyenne, WY 69.8%
Ardmore, OK 65.3%
US average 71.3%
Median AQI worse than US avg
Cheyenne, WY 47
Ardmore, OK 47
US average 41
Unhealthy days / yr better than US avg
Cheyenne, WY 0
Ardmore, OK 2
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Cheyenne, WY metro. Best year: 2020 (313 good days).

Year Good Moderate Unhealthy Median AQI
2020 313 48 2 39
2021 261 92 0 44
2022 297 66 0 42
2023 275 85 1 45
2024 271 91 1 45
2025 127 54 0 47

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Cheyenne, WY.

Ardmore, OK

AQI 47 · 65.3% good

47

Baltimore-Columbia-Towson, MD

AQI 47 · 62.2% good

47

Boise City, ID

AQI 47 · 64.7% good

47

Chico, CA

AQI 47 · 66.1% good

47

Columbus, GA-AL

AQI 47 · 58.8% good

47

Fort Wayne, IN

AQI 47 · 55.7% good

47

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Cheyenne, WY metro area? ▼
The Cheyenne, WY metro area has a median Air Quality Index (AQI) of 47, rated "Good." 69.8% of monitored days (127 out of 182) had good air quality in 2025.
How many unhealthy air days does Cheyenne, WY have? ▼
In 2025, the Cheyenne, WY metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 108.
Is air quality in Cheyenne, WY getting better or worse? ▼
Air quality in the Cheyenne, WY metro is worsening based on 5-year trends (2020-2025). Best year: 2020 with 313 good days. Worst year: 2025 with 127 good days.
What does AQI 47 mean for health? ▼
An AQI of 47 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Cheyenne, WY? ▼
The 90th percentile AQI for the Cheyenne, WY metro area is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 108 (USG).
How does Cheyenne, WY compare to other metro areas? ▼
The Cheyenne, WY metro has 69.8% good air days. Similar metros: Ardmore, OK (65.3% good), Baltimore-Columbia-Towson, MD (62.2% good), Boise City, ID (64.7% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. 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 files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.