Metro area air quality · 2025

Casper, WY

Median AQI 44 (Good). 85.6% of monitored days rated Good across this metro's EPA monitoring network.

44
Median AQI
85.6%
Good-air days
0
Unhealthy days
77%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 181 monitored days. EPA AQS →

The verdict

The Casper, WY metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 44 with 85.6% of 181 monitored days in the Good band.

44
median AQI · Good
85.6%
days rated Good
77%
cleaner than US metros
71
worst single reading

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

Insights: Casper, WY metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 44 over 181 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 155 Good days (86%), 26 Moderate (14%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 55 while the highest single-day reading hit 71 (Moderate). Metro residents averaged roughly 25.7 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -161 and the median AQI moved +2 points, which classifies the multi-year trajectory as stable. 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 Athens-Clarke County, GA (66.7% good, AQI 44); Bartlesville, OK (65.6% good, AQI 44); Bloomington, IL (64.1% good, AQI 44).

Air Quality Summary

Median AQI

44

Good

Good Days

85.6%

155 of 181 days

Max AQI

71

Moderate

Health Grade

Good

90th pct: 55

AQI Day Breakdown (2025)

Distribution of 181 monitored days across EPA AQI categories.

Good

155

86%

Moderate

26

14%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Casper, WY metro area's air quality is rated Good based on 85.6% 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 Casper, WY metro compare?

How Casper, WY compares

Good-day share better than US avg
Casper, WY 85.6%
Athens-Clarke County, GA 66.7%
US average 71.3%
Median AQI worse than US avg
Casper, WY 44
Athens-Clarke County, GA 44
US average 41
Unhealthy days / yr better than US avg
Casper, WY 0
Athens-Clarke County, GA 0
US average 1

5-Year Air Quality Trend

Air quality is stable in the Casper, WY metro. Best year: 2023 (344 good days).

Year Good Moderate Unhealthy Median AQI
2020 316 46 0 42
2021 282 77 0 42
2022 317 48 0 42
2023 344 20 0 42
2024 282 78 0 43
2025 155 26 0 44

Metros with Similar Air Quality

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

Athens-Clarke County, GA

AQI 44 · 66.7% good

44

Bartlesville, OK

AQI 44 · 65.6% good

44

Bloomington, IL

AQI 44 · 64.1% good

44

Boston-Cambridge-Newton, MA-NH

AQI 44 · 68.3% good

44

Bridgeport-Stamford-Norwalk, CT

AQI 44 · 66.8% good

44

Buffalo-Cheektowaga-Niagara Falls, NY

AQI 44 · 61.3% good

44

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 Casper, WY metro area? ▼
The Casper, WY metro area has a median Air Quality Index (AQI) of 44, rated "Good." 85.6% of monitored days (155 out of 181) had good air quality in 2025.
How many unhealthy air days does Casper, WY have? ▼
In 2025, the Casper, WY metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 71.
Is air quality in Casper, WY getting better or worse? ▼
Air quality in the Casper, WY metro is stable based on 5-year trends (2020-2025). Best year: 2023 with 344 good days. Worst year: 2025 with 155 good days.
What does AQI 44 mean for health? ▼
An AQI of 44 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 Casper, WY? ▼
The 90th percentile AQI for the Casper, WY metro area is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 71 (Moderate).
How does Casper, WY compare to other metro areas? ▼
The Casper, WY metro has 85.6% good air days. Similar metros: Athens-Clarke County, GA (66.7% good), Bartlesville, OK (65.6% good), Bloomington, IL (64.1% 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.