What is the air quality in Helena MT?

Helena MT, United States of America has an annual US AQI of 46 (Reasonable) and average PM2.5 of 7.8 µg/m³, ranking #478 of 5856 cities. Main pollutant: PM2.5.

What is the cleanest month in Helena MT?

October is typically the cleanest month (AQI 35) and August the most polluted (AQI 55).

Where does Helena MT's air quality data come from?

PM2.5: 1998–2026 (monitors 1999–2026, satellite 1998–2003, 2005; 2026 provisional (AirNow)). Measured by government monitoring stations. Full sources are on the methodology page.

Helena MT, United States of America — Air Quality & Clean City Guide 2026

Helena MT Air Quality Data

Global rank	City	Continent	AQI	PM2.5
478	Helena MT, United States of America	North America	AQI 46	PM2.5 7.8 µg/m³