Metro area air quality · 2025

Fond du Lac, WI

Median AQI 37 (Good). 91.5% of monitored days rated Good across this metro's EPA monitoring network.

Compiled by PlainAirData · August 23, 2026

37
Median AQI: 91.5%
Good-air days: 0
Unhealthy days: 89%
Cleaner than US metros

Fond du Lac, WI posted a 2025 median AQI of 37 (Good) with 91.5% Good days

According to the U.S. EPA Air Quality System, the Fond du Lac, WI CBSA recorded a median AQI of 37 across 199 monitored days in 2025, with 91.5% 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 Fond du Lac, WI CBSA's 91.5% Good-day share places it cleaner than 89% of US metros in 2025.
Closest median-AQI peer: Alexandria, LA (73.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Fond du Lac, WI.
2020–2025 Good-day shift: Fond du Lac, WI's Good-day share moved -4.1 points from 2020 to 2025 (median AQI +1).
Median AQI: Median AQI: 37

Aggregated from EPA Air Quality System (2025), 199 monitored days. EPA AQS →

The verdict

The Fond du Lac, WI metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 37 with 91.5% of 199 monitored days in the Good band.

37
median AQI · Good: 91.5%
days rated Good: 89%
cleaner than US metros: 80
worst single reading

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

Fond du Lac, WI metro's Good-day share fell from 92.7% to 91.5% between the 2024 and 2025 EPA annual releases, a change of -1.2 percentage points.

Insights: Fond du Lac, WI metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 199 measured days in 2025, which corresponds to a Good band and a Excellent metro-wide health grade. The monitored-day split lands at 182 Good days (91%), 17 Moderate (9%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 50 while the highest single-day reading hit 80 (Moderate). Metro residents averaged roughly 27.4 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -4.1 points and the median AQI moved +1 points, which classifies the multi-year trajectory as worsening. The metro recorded no Unhealthy-tier days in this annual dataset. Metros with comparable AQI profiles include Alexandria, LA (73.7% good, AQI 37); Athens, TN (78.2% good, AQI 37); Bennington, VT (83.6% good, AQI 37).

Air Quality Summary

Median AQI

Good

Good Days

91.5%

182 of 199 days

Max AQI

Moderate

Health Grade

Excellent

90th pct: 50

AQI Day Breakdown (2025)

Distribution of 199 monitored days across EPA AQI categories.

Good

182

91%

Moderate

USG

Unhealthy

Very Unhealthy

Hazardous

Health Impact Assessment

Excellent

The Fond du Lac, WI metro area's air quality is rated Excellent based on 91.5% 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 Fond du Lac, WI metro compare?

How Fond du Lac, WI compares

Compare against

Good-day share better than typical

Fond du Lac, WI 91.5%

Alexandria, LA 73.7%

Typical US metro 70.6%

Median AQI better than typical

Fond du Lac, WI 37

Alexandria, LA 37

Typical US metro 41

Unhealthy days / yr better than typical

Fond du Lac, WI 0

Alexandria, LA 0

Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Fond du Lac, WI metro. Highest Good-day share: 2020 (95.6%, 194 of 203 monitored days).

Year	Good	Moderate	Median AQI	Max AQI
2020	194	9	36	115
2021	178	30	39	90
2022	193	9	36	108
2023	162	38	41	122
2024	190	15	38	77
2025	182	17	37	80

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Fond du Lac, WI (37).

Alexandria, LA

Median AQI 37 · 73.7% Good-day share

Athens, TN

Median AQI 37 · 78.2% Good-day share

Bennington, VT

Median AQI 37 · 83.6% Good-day share

Blacksburg-Christiansburg-Radford, VA

Median AQI 37 · 94.4% Good-day share

Cadillac, MI

Median AQI 37 · 86.0% Good-day share

Chambersburg-Waynesboro, PA

Median AQI 37 · 91.5% Good-day share

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Fond du Lac, WI's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

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 Fond du Lac, WI metro area? ▼

The Fond du Lac, WI metro area has a median Air Quality Index (AQI) of 37, rated "Good." 91.5% of monitored days (182 out of 199) had good air quality in 2025.

How many unhealthy air days does Fond du Lac, WI have? ▼

In 2025, the Fond du Lac, WI metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 80.

Is air quality in Fond du Lac, WI getting better or worse? ▼

Air quality in the Fond du Lac, WI 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 95.6% (194 of 203 days). Lowest qualifying Good-day share: 2023 at 81.0% (162 of 200 days).

What does AQI 37 mean for health? ▼

An AQI of 37 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 Fond du Lac, WI? ▼

The 90th percentile AQI for the Fond du Lac, WI metro area is 50, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 80 (Moderate).

How does Fond du Lac, WI compare to other metro areas? ▼

The Fond du Lac, WI metro has 91.5% good air days. Similar metros: Alexandria, LA (73.7% good), Athens, TN (78.2% good), Bennington, VT (83.6% 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 Accessed 2026-07-06

Send the source-year summary or download its ready-to-use data card.

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Every figure on PlainAirData 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.