Great Falls, Mt. climate by month
Averages and records for each calendar month at Great Falls, Mt., United States, from 1997 to 2026. The warmest month is July, averaging 29.6°C; the coolest is February at 2.0°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 2.6°C | −7.9°C | 18.9°C26 January 2015 | −36.7°C12 January 2024 | 29 / 29 |
| February | 2.0°C | −8.9°C | 21.1°C5 February 2026 | −35.6°C12 February 2021 | 28 / 28 |
| March | 7.9°C | −4.4°C | 25.0°C30 March 2004 | −33.9°C3 March 2019 | 29 / 29 |
| April | 12.4°C | −0.4°C | 28.9°C28 April 2018 | −20.6°C21 April 2008 | 28 / 28 |
| May | 18.0°C | 4.6°C | 33.3°C31 May 2025 | −10.6°C1 May 2009 | 30 / 30 |
| June | 22.8°C | 8.8°C | 36.7°C14 June 2021 | −0.6°C11 June 2008 | 29 / 29 |
| July | 29.6°C | 12.8°C | 39.4°C19 July 2007 | 4.4°C4 July 2018 | 29 / 29 |
| August | 28.2°C | 11.8°C | 38.9°C1 August 2026 | 3.3°C1 August 1999 | 29 / 29 |
| September | 22.2°C | 7.7°C | 38.3°C3 September 2022 | −7.8°C23 September 2000 | 25 / 26 |
| October | 14.0°C | 1.7°C | 30.6°C3 October 2010 | −21.7°C31 October 2002 | 28 / 28 |
| November | 7.2°C | −3.2°C | 25.0°C7 November 1999 | −30.0°C28 November 2006 | 29 / 29 |
| December | 2.4°C | −7.6°C | 20.6°C1 December 2021 | −35.6°C21 December 2022 | 29 / 29 |
Years shows the number behind the average high, then the number holding a record for that month. They differ because a year contributes an average only when the month has at least 25 days of readings, while a single reading is enough to set a record. The average low is withheld on the same 25-day rule and is counted separately again; it is shown as a dash where the archive cannot support it. Across the twelve months here the averages rest on 25 to 30 years each.
See what Great Falls, Mt. is doing right now
Every figure on this page is computed from NOAA GHCN-Daily observations stored per station, per year, per month. Nothing is modelled, interpolated or estimated, and a month the archive never covered is left out rather than filled in. A station appears here only once all twelve months carry an average from at least 10 years. See how this is built.