Metro area air quality · 2025

Watertown-Fort Atkinson, WI

Median AQI 40 (Good). 84.8% of monitored days rated Good across this metro's EPA monitoring network.

40
Median AQI
84.8%
Good-air days
0
Unhealthy days
77%
Cleaner than US metros

Watertown-Fort Atkinson, WI posted a 2025 median AQI of 40 (Good) with 84.8% Good days

According to the U.S. EPA Air Quality System, the Watertown-Fort Atkinson, WI CBSA recorded a median AQI of 40 across 198 monitored days in 2025, with 84.8% 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 Watertown-Fort Atkinson, WI CBSA's 84.8% Good-day share places it cleaner than 77% of US metros in 2025.
Closest median-AQI peer
Altoona, PA (76.9% Good, median AQI 40) is the closest nationwide median-AQI peer to Watertown-Fort Atkinson, WI.
2020–2025 Good-day shift
Watertown-Fort Atkinson, WI's Good-day share moved -6.5 points from 2020 to 2025 (median AQI +2).
Median AQI
Median AQI: 40

Aggregated from EPA Air Quality System (2025), 198 monitored days. EPA AQS →

The verdict

The Watertown-Fort Atkinson, WI metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 40 with 84.8% of 198 monitored days in the Good band.

40
median AQI · Good
84.8%
days rated Good
77%
cleaner than US metros
105
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
  • Watertown-Fort Atkinson, WI metro's Good-day share fell from 89.3% to 85.3% between the 2024 and 2025 EPA annual releases, a change of -4.0 percentage points.
  • Watertown-Fort Atkinson, WI metro's peak single-day AQI rose from 93 to 105 between the 2024 and 2025 EPA annual releases, a change of +12 points.

Compared against 205 monitored days in 2024 and 197 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

Insights: Watertown-Fort Atkinson, WI metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 40 over 198 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 168 Good days (85%), 29 Moderate (15%), and 1 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 54 while the highest single-day reading hit 105 (USG). Metro residents averaged roughly 25.5 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 -6.5 points and the median AQI moved +2 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 Altoona, PA (76.9% good, AQI 40); Beaver Dam, WI (72.3% good, AQI 40); Bismarck, ND (76.7% good, AQI 40).

Air Quality Summary

Median AQI

40

Good

Good Days

84.8%

168 of 198 days

Max AQI

105

USG

Health Grade

Good

90th pct: 54

AQI Day Breakdown (2025)

Distribution of 198 monitored days across EPA AQI categories.

Good

168

85%

Moderate

29

15%

USG

1

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Watertown-Fort Atkinson, WI metro area's air quality is rated Good based on 84.8% 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 Watertown-Fort Atkinson, WI metro compare?

How Watertown-Fort Atkinson, WI compares

Good-day share better than typical
Watertown-Fort Atkinson, WI 84.8%
Altoona, PA 76.9%
Typical US metro 70.6%
Median AQI better than typical
Watertown-Fort Atkinson, WI 40
Altoona, PA 40
Typical US metro 41
Unhealthy days / yr better than typical
Watertown-Fort Atkinson, WI 0
Altoona, PA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Watertown-Fort Atkinson, WI metro. Highest Good-day share: 2022 (92.5%, 185 of 200 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 189 17 0 38
2021 178 29 0 40
2022 185 15 0 38
2023 145 43 0 44
2024 183 22 0 39
2025 168 29 0 40

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Watertown-Fort Atkinson, WI (40).

Altoona, PA

Median AQI 40 · 76.9% Good-day share

40

Beaver Dam, WI

Median AQI 40 · 72.3% Good-day share

40

Bismarck, ND

Median AQI 40 · 76.7% Good-day share

40

Cape Coral-Fort Myers, FL

Median AQI 40 · 76.4% Good-day share

40

College Station-Bryan, TX

Median AQI 40 · 68.5% Good-day share

40

Fallon, NV

Median AQI 40 · 85.2% Good-day share

40

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Watertown-Fort Atkinson, WI'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

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

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 Watertown-Fort Atkinson, WI metro area? ▼
The Watertown-Fort Atkinson, WI metro area has a median Air Quality Index (AQI) of 40, rated "Good." 84.8% of monitored days (168 out of 198) had good air quality in 2025.
How many unhealthy air days does Watertown-Fort Atkinson, WI have? ▼
In 2025, the Watertown-Fort Atkinson, WI metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 105.
Is air quality in Watertown-Fort Atkinson, WI getting better or worse? ▼
Air quality in the Watertown-Fort Atkinson, 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: 2022 at 92.5% (185 of 200 days). Lowest qualifying Good-day share: 2023 at 77.1% (145 of 188 days).
What does AQI 40 mean for health? ▼
An AQI of 40 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 Watertown-Fort Atkinson, WI? ▼
The 90th percentile AQI for the Watertown-Fort Atkinson, WI metro area is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 105 (USG).
How does Watertown-Fort Atkinson, WI compare to other metro areas? ▼
The Watertown-Fort Atkinson, WI metro has 84.8% good air days. Similar metros: Altoona, PA (76.9% good), Beaver Dam, WI (72.3% good), Bismarck, ND (76.7% 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

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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.