Climate Insights for Great Falls

The climate in Great Falls is cool. The average annual temperature is 8°C and approximately 532mm of precipitation falls per year. October is the wettest month, receiving around 82mm of rainfall. Great Falls is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are December, January, March, when temperatures can drop to -12°C. Snowfall occurs from January to December, with around 120cm accumulating over the season.

Great Falls has a wide annual temperature range, spanning 40°C from the coldest to warmest months. The warmest month is July, when average highs reach 28°C and the mean temperature sits around 20°C. The coldest month is December, when overnight lows fall to -12°C and the daily average is -9°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between November and December, with a 15°C shift in average temperatures.

Great Falls is a relatively dry area, receiving approximately 532mm of precipitation annually, which averages out to around 44mm per month. The wettest month is October, averaging 82mm of rainfall. May and April also tend to see above-average precipitation. The driest month is November, with just 7mm. That's 75mm less than October, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Snowfall is a regular feature from January to December, with around 120cm accumulating over the season. April typically sees the most snow at around 28cm.

Great Falls is relatively calm, with an average annual wind speed of 4km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 5km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 2km/h gap between the calmest and windiest months.

It is currently summer in Great Falls, which began on June 21, 2026. Great Falls is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 28°C, while the coldest stretch bottoms out in December near -12°C. Autumn is next, beginning on September 23, 2026 — 52 days from now.

The best time to visit Great Falls is during June, July and August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 41mm per month. By contrast, December can be quite cold with temperatures dropping to -12°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Great Falls based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.