Today | Weather | Wednesday, October 21, 2026

Weather in Great Falls, Montana

11:46 PM
Today
Cloudy Night
Day 73°
Night 45°
Precipitation 0 %
Wind 9 mph

Great Falls Weather Forecast Updated

Weather Forecast History
Last Year's Weather on This Day (October 21, 2025)
Cloudy Weather

Day

61°

Night

32°

Wind

19 mph

UV Index

30

Precipitation

0 %

Air Quality in Great Falls

NOW
21 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 1.44 µg/m³
PM10 2.3 µg/m³
O3 0.023 ppm
NO2 3.2 ppb
SO2 0 ppb
CO 0.10 ppm
NH3 1.1 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.5 – 1.44 µg/m³
PM10 – 2.3 µg/m³
O3 – 44.94 µg/m³
NO2 – 6.02 µg/m³
SO2 – 0.02 µg/m³
CO – 119.1 µg/m³
NH3 – 1.1 µg/m³
NO – 0 µg/m³