Metro area air quality · 2025
Eau Claire, WI
Median AQI 38 (Good). 73.7% of monitored days rated Good across this metro's EPA monitoring network.
- 38
- Median AQI
- 73.7%
- Good-air days
- 5
- Unhealthy days
- 53%
- Cleaner than US metros
Eau Claire, WI posted a 2025 median AQI of 38 (Good) with 73.7% Good days
According to the U.S. EPA Air Quality System, the Eau Claire, WI CBSA recorded a median AQI of 38 across 365 monitored days in 2025, with 73.7% rated Good and 5 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 Eau Claire, WI CBSA's 73.7% Good-day share places it cleaner than 53% of US metros in 2025.
- Closest median-AQI peer
- Appleton, WI (72.3% Good, median AQI 38) is the closest nationwide median-AQI peer to Eau Claire, WI.
- 2020–2025 Good-day shift
- Eau Claire, WI's Good-day share moved +5.0 points from 2020 to 2025 (median AQI -4).
- Median AQI
- Median AQI: 38
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Eau Claire, WI's peak reading 174 is in the upper max-AQI tercile among CBSA metros here. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 38 and 73.7% of 365 monitored days in the Good band.
- 38
- median AQI · Good
- 73.7%
- days rated Good
- 53%
- cleaner than US metros
- 174
- worst single reading
5 days reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Eau Claire, WI metro's Good-day share fell from 81.9% to 74.9% between the 2024 and 2025 EPA annual releases, a change of -7.0 percentage points.
- Eau Claire, WI metro's Unhealthy-category days rose from 0 to 5 between the 2024 and 2025 EPA annual releases, a change of +5 days.
- Eau Claire, WI metro's peak single-day AQI rose from 142 to 174 between the 2024 and 2025 EPA annual releases, a change of +32 points.
Eau Claire, WI's peak reading 174 is in the upper max-AQI tercile among CBSA metros here. Signature read: peak AQI 174 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 38 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 269 Good (74%), 85 Moderate (23%), and 6 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 62; the highest single-day reading hit 174 (Unhealthy).
Across 2020–2025, Good-day share shifted +5.0 points and median AQI moved -4 (improving). The annual record contains 5 days at Unhealthy or worse. Metros with comparable AQI profiles include Appleton, WI (72.3% good, AQI 38); Billings, MT (86.3% good, AQI 38); Burlington-South Burlington, VT (87.7% good, AQI 38).
Air Quality Summary
Median AQI
38
Good
Good Days
73.7%
269 of 365 days
Max AQI
174
Unhealthy
Health Grade
Moderate
90th pct: 62
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
269
74%
Moderate
85
23%
USG
6
2%
Unhealthy
5
1%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Eau Claire, WI metro area's air quality is rated Moderate based on 73.7% good air days. There were 5 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 6 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 174. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the Eau Claire, WI metro compare?
How Eau Claire, WI compares
5-Year Air Quality Trend
Air quality is improving in the Eau Claire, WI metro. Highest Good-day share: 2024 (81.9%, 299 of 365 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 256 | 110 | 0 | 42 | 93 |
| 2021 | 212 | 145 | 1 | 44 | 154 |
| 2022 | 268 | 97 | 0 | 41 | 81 |
| 2023 | 210 | 137 | 5 | 46 | 164 |
| 2024 | 299 | 66 | 0 | 38 | 142 |
| 2025 | 269 | 85 | 5 | 38 | 174 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Eau Claire, WI (38).
Appleton, WI
Median AQI 38 · 72.3% Good-day share
Billings, MT
Median AQI 38 · 86.3% Good-day share
Burlington-South Burlington, VT
Median AQI 38 · 87.7% Good-day share
Charlottesville, VA
Median AQI 38 · 81.0% Good-day share
Corning, NY
Median AQI 38 · 83.3% Good-day share
Dickinson, ND
Median AQI 38 · 82.7% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Eau Claire, WI's 5 (independent of median AQI).
Dallas-Fort Worth-Arlington, TX
5 unhealthy-or-worse days · median AQI 59
Hobbs, NM
5 unhealthy-or-worse days · median AQI 44
Mankato-North Mankato, MN
5 unhealthy-or-worse days · median AQI 42
Minot, ND
5 unhealthy-or-worse days · median AQI 36
Tucson, AZ
5 unhealthy-or-worse days · median AQI 54
Bakersfield, CA
4 unhealthy-or-worse days · median AQI 70
Frequently Asked Questions
What is the 90th percentile AQI for Eau Claire, WI? ▼
How many unhealthy air days does Eau Claire, WI have? ▼
What is the air quality in the Eau Claire, WI metro area? ▼
Is air quality in Eau Claire, WI getting better or worse? ▼
What does AQI 38 mean for health? ▼
How does Eau Claire, WI compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Eau Claire, WI, 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, Eau Claire, WI · 2020–2025