Montana · County air quality · 2025
Teton County, Montana
Median AQI 12 (Good). 97.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 12
- Median AQI
- 97.1%
- Good-air days
- 0
- Unhealthy days
- 96%
- Cleaner than US counties
Teton County's 2025 annual median AQI is 12 (Good), with 97.1% Good days
According to the U.S. EPA Air Quality System, Teton County, Montana posted a 2025 median AQI of 12 (Good) across 277 monitored days, with 97.1% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Teton County's 97.1% Good-day share places it cleaner than 96% of US counties in 2025.
- Closest median-AQI peer
- Beaverhead County (94.7% Good, median AQI 13) is the closest nationwide median-AQI peer to Teton County.
- 2024–2025 trend
- Teton County's floor-qualifying Good-day share is improving from 2024 to 2025 (92.3% → 97.1%).
- Median AQI
- Median AQI: 12
According to the 2025 EPA AQS county release on PlainAirData, Teton County, Montana ranks #14 of 951 by median AQI (12) and #35 by good-day share (97.1%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- Teton County's Good-day share rose from 92.3% to 97.1% between the 2024 and 2025 EPA annual releases, a change of +4.9 percentage points.
Data updated August 2026
- Good · 269 d · 97.1%
- Moderate · 8 d · 2.9%
How did Teton County's air break down in 2025?
Across 277 monitored days, 269 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 92 (Moderate).
EPA AQS →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where Teton County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Teton County's Good-day share is 97.1% - cleaner than 96% of that comparison set.
Teton County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
97.1% Cleaner than 96% higher than 96% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Teton County.
- PM2.5 · 277 days · 100.0%
2024 daily-monitor rhythm in Teton County
Month-by-month median AQI from EPA day-level county monitors (310 reported days in 2024). Jul posted the highest typical readings (median AQI 42, peak 101); May was cleanest at median 9. Summer months (Jun–Aug) averaged median AQI 30 vs 12 in Dec–Feb.
Health Impact Assessment
Teton County's air quality is rated Excellent based on 97.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 97.1% of monitored days in 2025, with a median AQI of 12. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 277 of 277 monitored days.
5-Year Air Quality Trend
Air quality is improving in Teton County. Highest Good-day share: 2025 (97.1%, 269 of 277 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2024 | 286 | 23 | 1 | 0 | 13 | 101 |
| 2025 | 269 | 8 | 0 | 0 | 12 | 92 |
How does Teton County compare?
How Teton County compares
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Teton County, Montana · 2020–2025
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
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.