Metro area air quality · 2025
Butte-Silver Bow, MT
Median AQI 28 (Good). 84.9% of monitored days rated Good across this metro's EPA monitoring network.
- 28
- Median AQI
- 84.9%
- Good-air days
- 0
- Unhealthy days
- 77%
- Cleaner than US metros
Butte-Silver Bow, MT posted a 2025 median AQI of 28 (Good) with 84.9% Good days
According to the U.S. EPA Air Quality System, the Butte-Silver Bow, MT CBSA recorded a median AQI of 28 across 365 monitored days in 2025, with 84.9% 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 Butte-Silver Bow, MT CBSA's 84.9% Good-day share places it cleaner than 77% of US metros in 2025.
- Closest median-AQI peer
- Dodge City, KS (89.8% Good, median AQI 28) is the closest nationwide median-AQI peer to Butte-Silver Bow, MT.
- 2020–2025 Good-day shift
- Butte-Silver Bow, MT's Good-day share moved +4.9 points from 2020 to 2025 (median AQI +6).
- Median AQI
- Median AQI: 28
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Butte-Silver Bow, MT sits in the upper Good-day tercile among EPA CBSA metros on this site (84.9% of 365 monitored days). On the EPA scale the metro runs good, cleaner than most US metros, with a median AQI of 28 and 84.9% of 365 monitored days in the Good band.
- 28
- median AQI · Good
- 84.9%
- days rated Good
- 77%
- cleaner than US metros
- 96
- 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
- Butte-Silver Bow, MT metro's Good-day share rose from 71.1% to 84.9% between the 2024 and 2025 EPA annual releases, a change of +13.9 percentage points.
- Butte-Silver Bow, MT metro's peak single-day AQI fell from 168 to 96 between the 2024 and 2025 EPA annual releases, a change of -72 points.
- Butte-Silver Bow, MT metro's Unhealthy-category days fell from 2 to 0 between the 2024 and 2025 EPA annual releases, a change of -2 days.
- Butte-Silver Bow, MT metro's median AQI fell from 31 to 28 between the 2024 and 2025 EPA annual releases, a change of -3 points.
Butte-Silver Bow, MT sits in the upper Good-day tercile among EPA CBSA metros on this site (84.9% of 365 monitored days). Signature read: 84.9% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 28 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 310 Good (85%), 55 Moderate (15%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 54; the highest single-day reading hit 96 (Moderate).
Across 2020–2025, Good-day share shifted +4.9 points and median AQI moved +6 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Dodge City, KS (89.8% good, AQI 28); Moses Lake, WA (79.7% good, AQI 28); Prineville, OR (72.9% good, AQI 28).
Air Quality Summary
Median AQI
28
Good
Good Days
84.9%
310 of 365 days
Max AQI
96
Moderate
Health Grade
Good
90th pct: 54
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
310
85%
Moderate
55
15%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Butte-Silver Bow, MT metro area's air quality is rated Good based on 84.9% 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 Butte-Silver Bow, MT metro compare?
How Butte-Silver Bow, MT compares
5-Year Air Quality Trend
Air quality is improving in the Butte-Silver Bow, MT metro. Highest Good-day share: 2025 (84.9%, 310 of 365 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 289 | 69 | 3 | 22 | 181 |
| 2021 | 256 | 89 | 6 | 33 | 163 |
| 2022 | 268 | 87 | 2 | 27 | 162 |
| 2023 | 268 | 94 | 0 | 31 | 124 |
| 2024 | 258 | 103 | 2 | 31 | 168 |
| 2025 | 310 | 55 | 0 | 28 | 96 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Butte-Silver Bow, MT (28).
Dodge City, KS
Median AQI 28 · 89.8% Good-day share
Moses Lake, WA
Median AQI 28 · 79.7% Good-day share
Prineville, OR
Median AQI 28 · 72.9% Good-day share
Aberdeen, SD
Median AQI 27 · 83.6% Good-day share
Albany, OR
Median AQI 27 · 80.0% Good-day share
Anchorage, AK
Median AQI 27 · 77.5% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Butte-Silver Bow, MT's 0 (independent of median AQI).
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-Schenectady-Troy, NY
0 unhealthy-or-worse days · median AQI 41
Alexandria, LA
0 unhealthy-or-worse days · median AQI 37
Frequently Asked Questions
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Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Butte-Silver Bow, MT, 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, Butte-Silver Bow, MT · 2020–2025