Missoula, MT Air Quality Index (AQI)
Live smoke and AQI for the Missoula area (Missoula County). We pull AirNow observations and forecasts, cross-check against the local engine, and flag stale data instead of hiding it. Peak smoke risk here runs mid-summer into fall, when Western wildfires and long-range plumes settle into the valleys.
About air quality in Missoula
Missoula is the 2nd most populous of the 5 Montana cities we track, with a population of about 75,516, in Missoula County.
In a city this size local sources contribute relatively little to PM2.5, so the AQI here tends to track transported smoke closely — when the number climbs, it is usually because smoke has arrived rather than because local conditions changed. That makes the reading a comparatively clean signal, but it also means it can move fast.
Smoke risk here concentrates in July through September, driven by fires across the northern Rockies and the Great Basin, with terrain that traps smoke overnight and clears it by afternoon. Outside that window an elevated reading in Missoula is more likely to be local — traffic, dust, or a temperature inversion holding everyday pollution near the ground — than wildfire smoke, and the dominant pollutant shown above is what tells the two apart.
How local is this reading? The AQI above is reported for a monitoring area, not for a street address. The nearest city we track is Helena, MT, about 95 miles away — far enough that conditions between the two can differ substantially, and worth checking both during an active plume.
Today & tomorrow
What each level means
| AQI | Level | What to do |
|---|---|---|
| 0–50 | Good | A great day to be active outside. |
| 51–100 | Moderate | Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors and watch for symptoms. |
| 101–150 | Unhealthy for Sensitive Groups | Sensitive groups should reduce prolonged or heavy exertion outdoors, take more breaks, and reschedule strenuous activities. |
| 151–200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should move activities indoors or reschedule. |
| 201–300 | Very Unhealthy | Everyone should avoid prolonged or heavy exertion and move activities indoors; sensitive groups should stay indoors and keep activity low. |
| 301–500 | Hazardous | Everyone should avoid all physical activity outdoors; stay indoors with clean air and keep activity low. |
Guidance paraphrased from EPA. Not medical advice — see disclaimer.
Nearby cities
All Montana cities · Smoke & your health · Can I go outside?
Missoula air quality FAQ
What is the air quality in Missoula right now?
The live AQI for Missoula, MT is shown at the top of this page, sourced from AirNow (U.S. EPA) and computed with the 2024 EPA standard, with the observation time and source labeled.
Is it safe to go outside in Missoula today?
It depends on the current AQI and whether you're in a sensitive group. At AQI 101–150 sensitive groups should cut back on prolonged outdoor exertion; at 151+ everyone should. Use our "Can I go outside?" tool for tailored guidance.
Why does Missoula's AQI here match AirNow?
Because AirNow is our display truth for US monitors — we show its reported number, never a self-computed value that disagrees with it for the same monitor.
When is wildfire smoke worst in Montana?
In the West, smoke risk peaks mid-summer through fall during active fire season and can linger in valleys.