Metro area air quality · 2025

Cheyenne, WY

Median AQI 45 (Good). 75.1% of monitored days rated Good across this metro's EPA monitoring network.

45
Median AQI
75.1%
Good-air days
0
Unhealthy days
57%
Cleaner than US metros

Cheyenne, WY posted a 2025 median AQI of 45 (Good) with 75.1% Good days

According to the U.S. EPA Air Quality System, the Cheyenne, WY CBSA recorded a median AQI of 45 across 365 monitored days in 2025, with 75.1% 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 Cheyenne, WY CBSA's 75.1% Good-day share places it cleaner than 57% of US metros in 2025.
Closest median-AQI peer
Akron, OH (61.6% Good, median AQI 45) is the closest nationwide median-AQI peer to Cheyenne, WY.
2020–2025 Good-day shift
Cheyenne, WY's Good-day share moved -11.0 points from 2020 to 2025 (median AQI +6).
Median AQI
Median AQI: 45

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

The verdict

Cheyenne, WY's median AQI 45 is in the upper (dirtier) CBSA tercile on this site. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 45 and 75.1% of 365 monitored days in the Good band.

45
median AQI · Good
75.1%
days rated Good
57%
cleaner than US metros
108
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
  • Cheyenne, WY metro's peak single-day AQI fell from 151 to 108 between the 2024 and 2025 EPA annual releases, a change of -43 points.
  • Cheyenne, WY metro's Unhealthy-category days fell from 1 to 0 between the 2024 and 2025 EPA annual releases, a change of -1 days.

Compared against 363 monitored days in 2024 and 364 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

Cheyenne, WY's median AQI 45 is in the upper (dirtier) CBSA tercile on this site. Signature read: median AQI 45 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 45 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 274 Good (75%), 90 Moderate (25%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 64; the highest single-day reading hit 108 (USG).

Across 2020–2025, Good-day share shifted -11.0 points and median AQI moved +6 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Akron, OH (61.6% good, AQI 45); Ardmore, OK (67.9% good, AQI 45); Asheville, NC (69.9% good, AQI 45).

Health effects of air pollution →

Air Quality Summary

Median AQI

45

Good

Good Days

75.1%

274 of 365 days

Max AQI

108

USG

Health Grade

Good

90th pct: 64

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

274

75%

Moderate

90

25%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Cheyenne, WY metro area's air quality is rated Good based on 75.1% 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 better than typical
Cheyenne, WY 75.1%
Akron, OH 61.6%
Typical US metro 70.6%
Median AQI worse than typical
Cheyenne, WY 45
Akron, OH 45
Typical US metro 41
Unhealthy days / yr better than typical
Cheyenne, WY 0
Akron, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Cheyenne, WY metro. Highest Good-day share: 2020 (86.2%, 313 of 363 monitored 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 274 90 0 45

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Cheyenne, WY (45).

Akron, OH

Median AQI 45 · 61.6% Good-day share

45

Ardmore, OK

Median AQI 45 · 67.9% Good-day share

45

Asheville, NC

Median AQI 45 · 69.9% Good-day share

45

Clinton, IA

Median AQI 45 · 59.5% Good-day share

45

Fort Dodge, IA

Median AQI 45 · 59.2% Good-day share

45

Gadsden, AL

Median AQI 45 · 61.4% Good-day share

45

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Cheyenne, WY'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

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Albany-Schenectady-Troy, NY

0 unhealthy-or-worse days · median AQI 41

41

Frequently Asked Questions

What does AQI 45 mean for health? ▼
An AQI of 45 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 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.
What is the air quality in the Cheyenne, WY metro area? ▼
The Cheyenne, WY metro area has a median Air Quality Index (AQI) of 45, rated "Good." 75.1% of monitored days (274 out of 365) had good air quality in 2025.
Is air quality in Cheyenne, WY getting better or worse? ▼
Air quality in the Cheyenne, WY metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 86.2% (313 of 363 days). Lowest qualifying Good-day share: 2021 at 73.9% (261 of 353 days).
How does Cheyenne, WY compare to other metro areas? ▼
The Cheyenne, WY metro has 75.1% good air days. Similar metros: Akron, OH (61.6% good), Ardmore, OK (67.9% good), Asheville, NC (69.9% good).
What is the 90th percentile AQI for Cheyenne, WY? ▼
The 90th percentile AQI for the Cheyenne, WY metro area is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 108 (USG).

Data Sources

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