Great Falls AP Weather Records (USW00024143)
Record envelope, standing records and threshold days for Great Falls AP (USW00024143), Montana, United States, with 90 years of record.
Key Facts for Great Falls AP
- Great Falls AP (USW00024143) is a weather station in Montana, United States at 47.47 latitude and -111.38 longitude, 1,118 m (3,667 ft) above sea level.
- The station reports from 1937 to 2026, 90 years of record.
- 1,464 records set at Great Falls AP still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Great Falls AP set a daily record snow depth of 15.2 cm (6.0 in) on 13 October 2026 (provisional).
Provisional Records
Records set in the last 60 days are provisional until they clear the revision window.
About the Station
- Location: Montana, United States, 47.47 latitude, -111.38 longitude.
- Elevation: 1,118 m (3,667 ft).
- Period of record: 1937 to 2026, 90 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
18 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 19.4 C (66.9 F) | -38.3 C (-36.9 F) | 17.8 C (64.0 F) | -22.8 C (-9.0 F) |
| Feb | 21.1 C (70.0 F) | -37.2 C (-35.0 F) | 21.1 C (70.0 F) | -27.2 C (-17.0 F) |
| Mar | 25.6 C (78.1 F) | -35.5 C (-31.9 F) | 24.4 C (75.9 F) | -21.1 C (-6.0 F) |
| Apr | 31.7 C (89.1 F) | -22.2 C (-8.0 F) | 26.7 C (80.1 F) | -7.8 C (18.0 F) |
| May | 33.9 C (93.0 F) | -11.1 C (12.0 F) | 31.7 C (89.1 F) | -5.0 C (23.0 F) |
| Jun | 38.3 C (100.9 F) | -0.6 C (30.9 F) | 29.4 C (84.9 F) | 3.3 C (37.9 F) |
| Jul | 40.6 C (105.1 F) | 2.2 C (36.0 F) | 38.3 C (100.9 F) | 6.7 C (44.1 F) |
| Aug | 41.1 C (106.0 F) | -1.1 C (30.0 F) | 38.9 C (102.0 F) | 3.3 C (37.9 F) |
| Sep | 38.9 C (102.0 F) | -11.0 C (12.2 F) | 31.1 C (88.0 F) | -2.2 C (28.0 F) |
| Oct | 32.8 C (91.0 F) | -23.9 C (-11.0 F) | 29.4 C (84.9 F) | -1.7 C (28.9 F) |
| Nov | 24.4 C (75.9 F) | -31.7 C (-25.1 F) | n/a | n/a |
| Dec | 20.6 C (69.1 F) | -41.7 C (-43.1 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1937 | 14 |
| 1938 | 10 |
| 1939 | 32 |
| 1940 | 13 |
| 1941 | 11 |
| 1942 | 12 |
| 1943 | 23 |
| 1944 | 7 |
| 1945 | 13 |
| 1946 | 11 |
| 1947 | 13 |
| 1948 | 10 |
| 1949 | 23 |
| 1950 | 26 |
| 1951 | 34 |
| 1952 | 8 |
| 1953 | 7 |
| 1954 | 30 |
| 1955 | 22 |
| 1956 | 22 |
| 1957 | 20 |
| 1958 | 21 |
| 1959 | 15 |
| 1960 | 24 |
| 1961 | 20 |
| 1962 | 17 |
| 1963 | 16 |
| 1964 | 15 |
| 1965 | 27 |
| 1966 | 19 |
| 1967 | 16 |
| 1968 | 18 |
| 1969 | 30 |
| 1970 | 12 |
| 1971 | 15 |
| 1972 | 24 |
| 1973 | 17 |
| 1974 | 10 |
| 1975 | 13 |
| 1976 | 10 |
| 1977 | 14 |
| 1978 | 8 |
| 1979 | 5 |
| 1980 | 23 |
| 1981 | 11 |
| 1982 | 13 |
| 1983 | 15 |
| 1984 | 18 |
| 1985 | 39 |
| 1986 | 18 |
| 1987 | 27 |
| 1988 | 13 |
| 1989 | 13 |
| 1990 | 18 |
| 1991 | 13 |
| 1992 | 32 |
| 1993 | 9 |
| 1994 | 19 |
| 1995 | 17 |
| 1996 | 17 |
| 1997 | 9 |
| 1998 | 5 |
| 1999 | 24 |
| 2000 | 12 |
| 2001 | 8 |
| 2002 | 23 |
| 2003 | 18 |
| 2004 | 14 |
| 2005 | 15 |
| 2006 | 7 |
| 2007 | 13 |
| 2008 | 13 |
| 2009 | 17 |
| 2010 | 7 |
| 2011 | 9 |
| 2012 | 11 |
| 2013 | 7 |
| 2014 | 13 |
| 2015 | 17 |
| 2016 | 6 |
| 2017 | 12 |
| 2018 | 7 |
| 2019 | 23 |
| 2020 | 22 |
| 2021 | 22 |
| 2022 | 24 |
| 2023 | 15 |
| 2024 | 17 |
| 2025 | 12 |
| 2026 | 20 |
All-Time Record Progression
7 new records| Date | Kind | Detail |
|---|---|---|
| 1968-12-29 | Record low maximum temperature | Record low maximum temperature -32.2 C (-26.0 F) |
| 1968-12-29 | Record low minimum temperature | Record low minimum temperature -41.7 C (-43.1 F) |
| 1973-04-20 | Record daily snowfall | Record daily snowfall 41.9 cm (16.5 in) |
| 1975-04-08 | Record snow depth | Record snow depth 48.3 cm (19.0 in) |
| 1975-04-09 | Record snow depth | Record snow depth 61.0 cm (24.0 in) |
| 1980-05-25 | Record daily precipitation | Record daily precipitation 63.5 mm (2.5 in) |
| 2014-08-23 | Record daily precipitation | Record daily precipitation 72.9 mm (2.9 in) |
Wettest Day of Each Month
Aug: 72.9 mm (2.9 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 18.3 mm (0.7 in) | 2 January 1955 |
| Feb | 22.4 mm (0.9 in) | 21 February 1951 |
| Mar | 26.9 mm (1.1 in) | 29 March 1977 |
| Apr | 55.9 mm (2.2 in) | 30 April 1951 |
| May | 63.5 mm (2.5 in) | 25 May 1980 |
| Jun | 61.5 mm (2.4 in) | 2 June 2005 |
| Jul | 40.9 mm (1.6 in) | 10 July 1983 |
| Aug | 72.9 mm (2.9 in) | 23 August 2014 |
| Sep | 39.6 mm (1.6 in) | 27 September 1982 |
| Oct | 57.9 mm (2.3 in) | 3 October 2015 |
| Nov | 24.4 mm (1.0 in) | 20 November 1946 |
| Dec | 19.6 mm (0.8 in) | 14 December 2015 |
Period of Record Coverage
1937 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1937 | 272 | 75% | No |
| 1938 | 365 | 100% | Yes |
| 1939 | 358 | 98% | Yes |
| 1940 | 366 | 100% | Yes |
| 1941 | 364 | 100% | Yes |
| 1942 | 364 | 100% | Yes |
| 1943 | 365 | 100% | Yes |
| 1944 | 366 | 100% | Yes |
| 1945 | 365 | 100% | Yes |
| 1946 | 365 | 100% | Yes |
| 1947 | 364 | 100% | Yes |
| 1948 | 366 | 100% | Yes |
| 1949 | 365 | 100% | Yes |
| 1950 | 365 | 100% | Yes |
| 1951 | 365 | 100% | Yes |
| 1952 | 366 | 100% | Yes |
| 1953 | 365 | 100% | Yes |
| 1954 | 365 | 100% | Yes |
| 1955 | 365 | 100% | Yes |
| 1956 | 366 | 100% | Yes |
| 1957 | 365 | 100% | Yes |
| 1958 | 365 | 100% | Yes |
| 1959 | 365 | 100% | Yes |
| 1960 | 366 | 100% | Yes |
| 1961 | 365 | 100% | Yes |
| 1962 | 365 | 100% | Yes |
| 1963 | 365 | 100% | Yes |
| 1964 | 366 | 100% | Yes |
| 1965 | 365 | 100% | Yes |
| 1966 | 365 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 366 | 100% | Yes |
| 1969 | 365 | 100% | Yes |
| 1970 | 365 | 100% | Yes |
| 1971 | 365 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 365 | 100% | Yes |
| 1974 | 365 | 100% | Yes |
| 1975 | 365 | 100% | Yes |
| 1976 | 366 | 100% | Yes |
| 1977 | 365 | 100% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 365 | 100% | Yes |
| 1980 | 366 | 100% | Yes |
| 1981 | 365 | 100% | Yes |
| 1982 | 365 | 100% | Yes |
| 1983 | 365 | 100% | Yes |
| 1984 | 366 | 100% | Yes |
| 1985 | 365 | 100% | Yes |
| 1986 | 365 | 100% | Yes |
| 1987 | 365 | 100% | Yes |
| 1988 | 366 | 100% | Yes |
| 1989 | 365 | 100% | Yes |
| 1990 | 365 | 100% | Yes |
| 1991 | 365 | 100% | Yes |
| 1992 | 366 | 100% | Yes |
| 1993 | 365 | 100% | Yes |
| 1994 | 365 | 100% | Yes |
| 1995 | 365 | 100% | Yes |
| 1996 | 366 | 100% | Yes |
| 1997 | 365 | 100% | Yes |
| 1998 | 365 | 100% | Yes |
| 1999 | 365 | 100% | Yes |
| 2000 | 366 | 100% | Yes |
| 2001 | 365 | 100% | Yes |
| 2002 | 365 | 100% | Yes |
| 2003 | 365 | 100% | Yes |
| 2004 | 366 | 100% | Yes |
| 2005 | 365 | 100% | Yes |
| 2006 | 365 | 100% | Yes |
| 2007 | 365 | 100% | Yes |
| 2008 | 366 | 100% | Yes |
| 2009 | 365 | 100% | Yes |
| 2010 | 365 | 100% | Yes |
| 2011 | 365 | 100% | Yes |
| 2012 | 366 | 100% | Yes |
| 2013 | 365 | 100% | Yes |
| 2014 | 365 | 100% | Yes |
| 2015 | 365 | 100% | Yes |
| 2016 | 366 | 100% | Yes |
| 2017 | 365 | 100% | Yes |
| 2018 | 365 | 100% | Yes |
| 2019 | 365 | 100% | Yes |
| 2020 | 366 | 100% | Yes |
| 2021 | 365 | 100% | Yes |
| 2022 | 365 | 100% | Yes |
| 2023 | 365 | 100% | Yes |
| 2024 | 366 | 100% | Yes |
| 2025 | 365 | 100% | Yes |
| 2026 | 286 | 78% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 13 October 2026 | Great Falls AP, US | daily snow depth (Provisional) | 15.2 cm (6.0 in) | 5.0 cm (2.0 in) | 44 years | 32 of 100 (Routine) |
| 12 October 2026 | Great Falls AP, US | monthly snow depth (Provisional) | 25.4 cm (10.0 in) | 0.4 cm (0.2 in) | 5 years | 20 of 100 (Routine) |
| 11 October 2026 | Great Falls AP, US | daily snow depth (Provisional) | 20.3 cm (8.0 in) | 10.3 cm (4.1 in) | 7 years | 33 of 100 (Routine) |
| 11 October 2026 | Great Falls AP, US | monthly snowfall (Provisional) | 23.6 cm (9.3 in) | 2.8 cm (1.1 in) | 5 years | 27 of 100 (Routine) |
| 10 October 2026 | Great Falls AP, US | daily snowfall (Provisional) | 16.3 cm (6.4 in) | 11.0 cm (4.3 in) | 53 years | 52 of 100 (Notable) |
| 10 October 2026 | Great Falls AP, US | daily rain (Provisional) | 32.8 mm (1.3 in) | 16.3 mm (0.6 in) | 28 years | 50 of 100 (Notable) |
| 5 October 2026 | Great Falls AP, US | daily high max (Provisional) | 29.4 C (84.9 F) | 1.1 C (2.0 F) | 4 years | 11 of 100 (Routine) |
| 14 August 2026 | Great Falls AP, US | daily rain | 18.8 mm (0.7 in) | 5.3 mm (0.21 in) | 16 years | 20 of 100 (Routine) |
| 5 August 2026 | Great Falls AP, US | daily low min | 5.6 C (42.1 F) | 1.1 C (2.0 F) | 4 years | 13 of 100 (Routine) |
| 4 August 2026 | Great Falls AP, US | daily low min | 3.3 C (37.9 F) | 1.7 C (3.1 F) | 44 years | 27 of 100 (Routine) |
| 1 August 2026 | Great Falls AP, US | daily high max | 38.9 C (102.0 F) | 0.6 C (1.1 F) | 4 years | 11 of 100 (Routine) |
| 25 July 2026 | Great Falls AP, US | daily high max | 38.3 C (100.9 F) | 2.7 C (4.9 F) | 83 years | 38 of 100 (Notable) |
| 28 June 2026 | Great Falls AP, US | daily rain | 41.1 mm (1.6 in) | 7.3 mm (0.29 in) | 44 years | 31 of 100 (Routine) |
| 31 May 2026 | Great Falls AP, US | daily rain (Tie) | 30.5 mm (1.2 in) | tie | 25 years | 4 of 100 (Routine) |
| 26 May 2026 | Great Falls AP, US | daily high max (Tie) | 31.1 C (88.0 F) | tie | 60 years | 6 of 100 (Routine) |
| 13 May 2026 | Great Falls AP, US | daily high max | 31.7 C (89.1 F) | 1.7 C (3.1 F) | 24 years | 18 of 100 (Routine) |
| 6 May 2026 | Great Falls AP, US | daily low min | -5.0 C (23.0 F) | 2.2 C (4.0 F) | 65 years | 33 of 100 (Routine) |
| 5 May 2026 | Great Falls AP, US | daily low min | -3.9 C (25.0 F) | 0.6 C (1.1 F) | 59 years | 27 of 100 (Routine) |
| 21 April 2026 | Great Falls AP, US | daily high max (Tie) | 26.7 C (80.1 F) | tie | 84 years | 8 of 100 (Routine) |
| 3 April 2026 | Great Falls AP, US | daily snow depth (Tie) | 17.8 cm (7.0 in) | tie | 48 years | 5 of 100 (Routine) |
Climate Trend
88 complete years, 1938 to 2025| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1938 | 8.0 C | +0.78 C |
| 1939 | 9.2 C | +1.93 C |
| 1940 | 7.9 C | +0.61 C |
| 1941 | 8.1 C | +0.88 C |
| 1942 | 7.3 C | +0.02 C |
| 1943 | 7.4 C | +0.16 C |
| 1944 | 7.9 C | +0.65 C |
| 1945 | 7.2 C | -0.01 C |
| 1946 | 8.0 C | +0.75 C |
| 1947 | 7.5 C | +0.26 C |
| 1948 | 6.9 C | -0.32 C |
| 1949 | 7.1 C | -0.20 C |
| 1950 | 5.9 C | -1.40 C |
| 1951 | 4.7 C | -2.57 C |
| 1952 | 7.7 C | +0.48 C |
| 1953 | 8.9 C | +1.67 C |
| 1954 | 7.2 C | -0.01 C |
| 1955 | 5.7 C | -1.60 C |
| 1956 | 7.5 C | +0.25 C |
| 1957 | 6.9 C | -0.31 C |
| 1958 | 8.2 C | +0.97 C |
| 1959 | 7.0 C | -0.23 C |
| 1960 | 7.7 C | +0.48 C |
| 1961 | 8.2 C | +0.93 C |
| 1962 | 7.1 C | -0.12 C |
| 1963 | 8.3 C | +1.08 C |
| 1964 | 7.0 C | -0.23 C |
| 1965 | 6.7 C | -0.57 C |
| 1966 | 7.1 C | -0.18 C |
| 1967 | 7.6 C | +0.38 C |
| 1968 | 6.9 C | -0.33 C |
| 1969 | 6.1 C | -1.19 C |
| 1970 | 6.7 C | -0.52 C |
| 1971 | 7.0 C | -0.23 C |
| 1972 | 6.3 C | -0.95 C |
| 1973 | 8.0 C | +0.75 C |
| 1974 | 8.3 C | +1.06 C |
| 1975 | 5.6 C | -1.70 C |
| 1976 | 8.4 C | +1.19 C |
| 1977 | 7.2 C | -0.02 C |
| 1978 | 5.2 C | -2.08 C |
| 1979 | 6.9 C | -0.36 C |
| 1980 | 7.6 C | +0.36 C |
| 1981 | 8.4 C | +1.17 C |
| 1982 | 5.0 C | -2.29 C |
| 1983 | 7.1 C | -0.17 C |
| 1984 | 7.2 C | -0.07 C |
| 1985 | 5.7 C | -1.59 C |
| 1986 | 8.2 C | +0.92 C |
| 1987 | 9.3 C | +2.06 C |
| 1988 | 8.6 C | +1.34 C |
| 1989 | 6.4 C | -0.83 C |
| 1990 | 7.6 C | +0.31 C |
| 1991 | 7.8 C | +0.51 C |
| 1992 | 8.1 C | +0.87 C |
| 1993 | 5.7 C | -1.60 C |
| 1994 | 7.4 C | +0.10 C |
| 1995 | 6.4 C | -0.89 C |
| 1996 | 4.6 C | -2.70 C |
| 1997 | 6.8 C | -0.42 C |
| 1998 | 7.6 C | +0.38 C |
| 1999 | 8.0 C | +0.71 C |
| 2000 | 6.8 C | -0.42 C |
| 2001 | 7.9 C | +0.65 C |
| 2002 | 6.2 C | -1.09 C |
| 2003 | 7.6 C | +0.38 C |
| 2004 | 7.3 C | +0.00 C |
| 2005 | 7.2 C | -0.01 C |
| 2006 | 8.4 C | +1.16 C |
| 2007 | 8.2 C | +0.93 C |
| 2008 | 6.7 C | -0.51 C |
| 2009 | 6.5 C | -0.75 C |
| 2010 | 6.8 C | -0.41 C |
| 2011 | 6.8 C | -0.48 C |
| 2012 | 8.6 C | +1.30 C |
| 2013 | 7.7 C | +0.40 C |
| 2014 | 6.7 C | -0.60 C |
| 2015 | 8.3 C | +1.01 C |
| 2016 | 8.1 C | +0.82 C |
| 2017 | 7.1 C | -0.12 C |
| 2018 | 6.4 C | -0.89 C |
| 2019 | 5.2 C | -2.08 C |
| 2020 | 7.5 C | +0.24 C |
| 2021 | 7.5 C | +0.28 C |
| 2022 | 6.8 C | -0.42 C |
| 2023 | 8.3 C | +1.01 C |
| 2024 | 7.9 C | +0.66 C |
| 2025 | 7.8 C | +0.58 C |
The fitted trend in annual mean temperature here over 1938 to 2025 is -0.02 C (-0.10 to 0.06) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.03 F (-0.18 to 0.11) per decade. The slope is a straight line fitted to 88 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | -0.02 C (-0.10 to 0.06) per decade | -0.03 F (-0.18 to 0.11) per decade | 1938 to 2025 | 88 | Not clearly different from zero |
| Mean daily maximum | 0.12 C (0.03 to 0.22) per decade | 0.2 F (0.1 to 0.4) per decade | 1938 to 2025 | 88 | Rise |
| Mean daily minimum | -0.2 C (-0.2 to -0.1) per decade | -0.3 F (-0.4 to -0.2) per decade | 1938 to 2025 | 88 | Fall |
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1937 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 41.1 C (106.0 F) | 1961 | 37.2 C (99.0 F) | 90 |
| Coldest night (TNn) | -41.7 C (-43.1 F) | 1968 | -31.7 C (-25.1 F) | 90 |
| Wettest day (Rx1day) | 72.9 mm (2.9 in) | 2014 | 31.4 mm (1.2 in) | 90 |
| Wettest five days (Rx5day) | 113.1 mm (4.5 in) | 1953 | 53.0 mm (2.1 in) | 90 |
| Longest dry spell (CDD) | 73 days | 1964 | 32 days | 90 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1937 | 38.3 C (100.9 F) |
| 1938 | 35.6 C (96.1 F) |
| 1939 | 37.8 C (100.0 F) |
| 1940 | 40.6 C (105.1 F) |
| 1941 | 37.2 C (99.0 F) |
| 1942 | 36.1 C (97.0 F) |
| 1943 | 35.6 C (96.1 F) |
| 1944 | 34.4 C (93.9 F) |
| 1945 | 36.1 C (97.0 F) |
| 1946 | 35.6 C (96.1 F) |
| 1947 | 36.7 C (98.1 F) |
| 1948 | 35.0 C (95.0 F) |
| 1949 | 38.3 C (100.9 F) |
| 1950 | 34.4 C (93.9 F) |
| 1951 | 35.6 C (96.1 F) |
| 1952 | 35.0 C (95.0 F) |
| 1953 | 38.9 C (102.0 F) |
| 1954 | 36.1 C (97.0 F) |
| 1955 | 36.1 C (97.0 F) |
| 1956 | 34.4 C (93.9 F) |
| 1957 | 35.6 C (96.1 F) |
| 1958 | 35.0 C (95.0 F) |
| 1959 | 36.7 C (98.1 F) |
| 1960 | 38.9 C (102.0 F) |
| 1961 | 41.1 C (106.0 F) |
| 1962 | 34.4 C (93.9 F) |
| 1963 | 37.8 C (100.0 F) |
| 1964 | 38.3 C (100.9 F) |
| 1965 | 37.8 C (100.0 F) |
| 1966 | 36.1 C (97.0 F) |
| 1967 | 36.7 C (98.1 F) |
| 1968 | 36.1 C (97.0 F) |
| 1969 | 41.1 C (106.0 F) |
| 1970 | 38.3 C (100.9 F) |
| 1971 | 38.3 C (100.9 F) |
| 1972 | 36.7 C (98.1 F) |
| 1973 | 40.6 C (105.1 F) |
| 1974 | 37.2 C (99.0 F) |
| 1975 | 40.0 C (104.0 F) |
| 1976 | 37.2 C (99.0 F) |
| 1977 | 35.0 C (95.0 F) |
| 1978 | 37.2 C (99.0 F) |
| 1979 | 37.8 C (100.0 F) |
| 1980 | 36.7 C (98.1 F) |
| 1981 | 38.3 C (100.9 F) |
| 1982 | 34.4 C (93.9 F) |
| 1983 | 40.0 C (104.0 F) |
| 1984 | 40.0 C (104.0 F) |
| 1985 | 38.3 C (100.9 F) |
| 1986 | 36.7 C (98.1 F) |
| 1987 | 36.7 C (98.1 F) |
| 1988 | 37.2 C (99.0 F) |
| 1989 | 36.1 C (97.0 F) |
| 1990 | 38.9 C (102.0 F) |
| 1991 | 37.2 C (99.0 F) |
| 1992 | 36.1 C (97.0 F) |
| 1993 | 33.9 C (93.0 F) |
| 1994 | 35.6 C (96.1 F) |
| 1995 | 35.6 C (96.1 F) |
| 1996 | 38.3 C (100.9 F) |
| 1997 | 34.4 C (93.9 F) |
| 1998 | 37.2 C (99.0 F) |
| 1999 | 37.2 C (99.0 F) |
| 2000 | 37.8 C (100.0 F) |
| 2001 | 37.8 C (100.0 F) |
| 2002 | 38.9 C (102.0 F) |
| 2003 | 39.4 C (102.9 F) |
| 2004 | 37.2 C (99.0 F) |
| 2005 | 36.7 C (98.1 F) |
| 2006 | 37.8 C (100.0 F) |
| 2007 | 40.0 C (104.0 F) |
| 2008 | 36.7 C (98.1 F) |
| 2009 | 35.0 C (95.0 F) |
| 2010 | 35.6 C (96.1 F) |
| 2011 | 37.2 C (99.0 F) |
| 2012 | 38.9 C (102.0 F) |
| 2013 | 38.3 C (100.9 F) |
| 2014 | 35.0 C (95.0 F) |
| 2015 | 37.8 C (100.0 F) |
| 2016 | 36.1 C (97.0 F) |
| 2017 | 38.3 C (100.9 F) |
| 2018 | 38.9 C (102.0 F) |
| 2019 | 36.7 C (98.1 F) |
| 2020 | 37.2 C (99.0 F) |
| 2021 | 37.2 C (99.0 F) |
| 2022 | 38.9 C (102.0 F) |
| 2023 | 38.3 C (100.9 F) |
| 2024 | 39.4 C (102.9 F) |
| 2025 | 37.8 C (100.0 F) |
| 2026 | 38.9 C (102.0 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1937 | -26.7 C (-16.1 F) |
| 1938 | -30.0 C (-22.0 F) |
| 1939 | -37.2 C (-35.0 F) |
| 1940 | -28.3 C (-18.9 F) |
| 1941 | -30.6 C (-23.1 F) |
| 1942 | -30.6 C (-23.1 F) |
| 1943 | -35.6 C (-32.1 F) |
| 1944 | -22.2 C (-8.0 F) |
| 1945 | -26.1 C (-15.0 F) |
| 1946 | -28.9 C (-20.0 F) |
| 1947 | -30.0 C (-22.0 F) |
| 1948 | -28.9 C (-20.0 F) |
| 1949 | -33.9 C (-29.0 F) |
| 1950 | -36.1 C (-33.0 F) |
| 1951 | -33.9 C (-29.0 F) |
| 1952 | -31.7 C (-25.1 F) |
| 1953 | -21.1 C (-6.0 F) |
| 1954 | -36.1 C (-33.0 F) |
| 1955 | -30.6 C (-23.1 F) |
| 1956 | -30.6 C (-23.1 F) |
| 1957 | -35.0 C (-31.0 F) |
| 1958 | -23.3 C (-9.9 F) |
| 1959 | -33.3 C (-27.9 F) |
| 1960 | -30.6 C (-23.1 F) |
| 1961 | -28.9 C (-20.0 F) |
| 1962 | -31.7 C (-25.1 F) |
| 1963 | -32.2 C (-26.0 F) |
| 1964 | -37.8 C (-36.0 F) |
| 1965 | -28.9 C (-20.0 F) |
| 1966 | -30.6 C (-23.1 F) |
| 1967 | -32.8 C (-27.0 F) |
| 1968 | -41.7 C (-43.1 F) |
| 1969 | -38.3 C (-36.9 F) |
| 1970 | -27.2 C (-17.0 F) |
| 1971 | -34.4 C (-29.9 F) |
| 1972 | -37.8 C (-36.0 F) |
| 1973 | -27.8 C (-18.0 F) |
| 1974 | -33.3 C (-27.9 F) |
| 1975 | -31.1 C (-24.0 F) |
| 1976 | -28.9 C (-20.0 F) |
| 1977 | -32.8 C (-27.0 F) |
| 1978 | -31.1 C (-24.0 F) |
| 1979 | -33.3 C (-27.9 F) |
| 1980 | -34.4 C (-29.9 F) |
| 1981 | -31.1 C (-24.0 F) |
| 1982 | -35.6 C (-32.1 F) |
| 1983 | -41.1 C (-42.0 F) |
| 1984 | -32.2 C (-26.0 F) |
| 1985 | -33.9 C (-29.0 F) |
| 1986 | -30.0 C (-22.0 F) |
| 1987 | -23.9 C (-11.0 F) |
| 1988 | -26.1 C (-15.0 F) |
| 1989 | -37.2 C (-35.0 F) |
| 1990 | -37.2 C (-35.0 F) |
| 1991 | -26.7 C (-16.1 F) |
| 1992 | -31.1 C (-24.0 F) |
| 1993 | -31.7 C (-25.1 F) |
| 1994 | -36.7 C (-34.1 F) |
| 1995 | -32.2 C (-26.0 F) |
| 1996 | -37.2 C (-35.0 F) |
| 1997 | -35.0 C (-31.0 F) |
| 1998 | -34.4 C (-29.9 F) |
| 1999 | -26.1 C (-15.0 F) |
| 2000 | -30.0 C (-22.0 F) |
| 2001 | -24.4 C (-11.9 F) |
| 2002 | -30.0 C (-22.0 F) |
| 2003 | -28.9 C (-20.0 F) |
| 2004 | -32.2 C (-26.0 F) |
| 2005 | -35.0 C (-31.0 F) |
| 2006 | -31.7 C (-25.1 F) |
| 2007 | -25.6 C (-14.1 F) |
| 2008 | -31.7 C (-25.1 F) |
| 2009 | -32.2 C (-26.0 F) |
| 2010 | -29.4 C (-20.9 F) |
| 2011 | -31.1 C (-24.0 F) |
| 2012 | -29.4 C (-20.9 F) |
| 2013 | -36.0 C (-32.8 F) |
| 2014 | -36.6 C (-33.9 F) |
| 2015 | -27.7 C (-17.9 F) |
| 2016 | -32.1 C (-25.8 F) |
| 2017 | -32.1 C (-25.8 F) |
| 2018 | -32.7 C (-26.9 F) |
| 2019 | -35.5 C (-31.9 F) |
| 2020 | -27.7 C (-17.9 F) |
| 2021 | -36.0 C (-32.8 F) |
| 2022 | -35.5 C (-31.9 F) |
| 2023 | -29.9 C (-21.8 F) |
| 2024 | -38.2 C (-36.8 F) |
| 2025 | -33.8 C (-28.8 F) |
| 2026 | -27.2 C (-17.0 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1937 | 31.2 mm (1.2 in) |
| 1938 | 28.2 mm (1.1 in) |
| 1939 | 19.3 mm (0.8 in) |
| 1940 | 18.3 mm (0.7 in) |
| 1941 | 22.1 mm (0.9 in) |
| 1942 | 21.6 mm (0.9 in) |
| 1943 | 31.5 mm (1.2 in) |
| 1944 | 26.2 mm (1.0 in) |
| 1945 | 35.3 mm (1.4 in) |
| 1946 | 24.4 mm (1.0 in) |
| 1947 | 48.5 mm (1.9 in) |
| 1948 | 39.1 mm (1.5 in) |
| 1949 | 39.4 mm (1.6 in) |
| 1950 | 43.7 mm (1.7 in) |
| 1951 | 55.9 mm (2.2 in) |
| 1952 | 21.1 mm (0.8 in) |
| 1953 | 61.0 mm (2.4 in) |
| 1954 | 50.0 mm (2.0 in) |
| 1955 | 28.2 mm (1.1 in) |
| 1956 | 18.5 mm (0.7 in) |
| 1957 | 44.7 mm (1.8 in) |
| 1958 | 34.5 mm (1.4 in) |
| 1959 | 41.4 mm (1.6 in) |
| 1960 | 22.6 mm (0.9 in) |
| 1961 | 16.3 mm (0.6 in) |
| 1962 | 36.3 mm (1.4 in) |
| 1963 | 19.8 mm (0.8 in) |
| 1964 | 57.9 mm (2.3 in) |
| 1965 | 35.6 mm (1.4 in) |
| 1966 | 24.6 mm (1.0 in) |
| 1967 | 22.9 mm (0.9 in) |
| 1968 | 32.3 mm (1.3 in) |
| 1969 | 54.9 mm (2.2 in) |
| 1970 | 21.6 mm (0.9 in) |
| 1971 | 15.2 mm (0.6 in) |
| 1972 | 23.9 mm (0.9 in) |
| 1973 | 42.9 mm (1.7 in) |
| 1974 | 40.1 mm (1.6 in) |
| 1975 | 35.1 mm (1.4 in) |
| 1976 | 37.3 mm (1.5 in) |
| 1977 | 31.8 mm (1.3 in) |
| 1978 | 32.8 mm (1.3 in) |
| 1979 | 22.6 mm (0.9 in) |
| 1980 | 63.5 mm (2.5 in) |
| 1981 | 20.8 mm (0.8 in) |
| 1982 | 39.6 mm (1.6 in) |
| 1983 | 40.9 mm (1.6 in) |
| 1984 | 37.8 mm (1.5 in) |
| 1985 | 29.5 mm (1.2 in) |
| 1986 | 22.9 mm (0.9 in) |
| 1987 | 30.2 mm (1.2 in) |
| 1988 | 27.7 mm (1.1 in) |
| 1989 | 48.0 mm (1.9 in) |
| 1990 | 40.1 mm (1.6 in) |
| 1991 | 48.5 mm (1.9 in) |
| 1992 | 22.4 mm (0.9 in) |
| 1993 | 31.0 mm (1.2 in) |
| 1994 | 21.1 mm (0.8 in) |
| 1995 | 32.3 mm (1.3 in) |
| 1996 | 28.7 mm (1.1 in) |
| 1997 | 30.0 mm (1.2 in) |
| 1998 | 47.8 mm (1.9 in) |
| 1999 | 23.9 mm (0.9 in) |
| 2000 | 30.5 mm (1.2 in) |
| 2001 | 26.7 mm (1.1 in) |
| 2002 | 56.9 mm (2.2 in) |
| 2003 | 19.1 mm (0.8 in) |
| 2004 | 34.8 mm (1.4 in) |
| 2005 | 61.5 mm (2.4 in) |
| 2006 | 42.7 mm (1.7 in) |
| 2007 | 22.9 mm (0.9 in) |
| 2008 | 32.5 mm (1.3 in) |
| 2009 | 24.1 mm (0.9 in) |
| 2010 | 32.0 mm (1.3 in) |
| 2011 | 28.4 mm (1.1 in) |
| 2012 | 27.7 mm (1.1 in) |
| 2013 | 19.3 mm (0.8 in) |
| 2014 | 72.9 mm (2.9 in) |
| 2015 | 57.9 mm (2.3 in) |
| 2016 | 21.6 mm (0.9 in) |
| 2017 | 27.9 mm (1.1 in) |
| 2018 | 35.6 mm (1.4 in) |
| 2019 | 17.0 mm (0.7 in) |
| 2020 | 52.1 mm (2.1 in) |
| 2021 | 24.6 mm (1.0 in) |
| 2022 | 34.0 mm (1.3 in) |
| 2023 | 34.8 mm (1.4 in) |
| 2024 | 30.5 mm (1.2 in) |
| 2025 | 29.2 mm (1.1 in) |
| 2026 | 41.1 mm (1.6 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1937 | 51.7 mm (2.0 in) |
| 1938 | 70.3 mm (2.8 in) |
| 1939 | 30.5 mm (1.2 in) |
| 1940 | 36.4 mm (1.4 in) |
| 1941 | 47.2 mm (1.9 in) |
| 1942 | 55.9 mm (2.2 in) |
| 1943 | 49.0 mm (1.9 in) |
| 1944 | 38.4 mm (1.5 in) |
| 1945 | 53.8 mm (2.1 in) |
| 1946 | 29.2 mm (1.1 in) |
| 1947 | 61.0 mm (2.4 in) |
| 1948 | 61.8 mm (2.4 in) |
| 1949 | 50.1 mm (2.0 in) |
| 1950 | 53.9 mm (2.1 in) |
| 1951 | 73.7 mm (2.9 in) |
| 1952 | 22.6 mm (0.9 in) |
| 1953 | 113.1 mm (4.5 in) |
| 1954 | 76.1 mm (3.0 in) |
| 1955 | 49.8 mm (2.0 in) |
| 1956 | 32.7 mm (1.3 in) |
| 1957 | 61.7 mm (2.4 in) |
| 1958 | 55.6 mm (2.2 in) |
| 1959 | 56.9 mm (2.2 in) |
| 1960 | 46.0 mm (1.8 in) |
| 1961 | 25.6 mm (1.0 in) |
| 1962 | 54.4 mm (2.1 in) |
| 1963 | 33.0 mm (1.3 in) |
| 1964 | 87.6 mm (3.4 in) |
| 1965 | 69.9 mm (2.8 in) |
| 1966 | 27.6 mm (1.1 in) |
| 1967 | 43.9 mm (1.7 in) |
| 1968 | 51.8 mm (2.0 in) |
| 1969 | 106.4 mm (4.2 in) |
| 1970 | 55.2 mm (2.2 in) |
| 1971 | 32.3 mm (1.3 in) |
| 1972 | 29.8 mm (1.2 in) |
| 1973 | 49.0 mm (1.9 in) |
| 1974 | 51.0 mm (2.0 in) |
| 1975 | 78.2 mm (3.1 in) |
| 1976 | 61.2 mm (2.4 in) |
| 1977 | 41.0 mm (1.6 in) |
| 1978 | 53.5 mm (2.1 in) |
| 1979 | 54.1 mm (2.1 in) |
| 1980 | 109.2 mm (4.3 in) |
| 1981 | 37.6 mm (1.5 in) |
| 1982 | 68.3 mm (2.7 in) |
| 1983 | 74.4 mm (2.9 in) |
| 1984 | 38.1 mm (1.5 in) |
| 1985 | 66.7 mm (2.6 in) |
| 1986 | 49.8 mm (2.0 in) |
| 1987 | 43.2 mm (1.7 in) |
| 1988 | 44.7 mm (1.8 in) |
| 1989 | 97.1 mm (3.8 in) |
| 1990 | 73.6 mm (2.9 in) |
| 1991 | 69.3 mm (2.7 in) |
| 1992 | 54.1 mm (2.1 in) |
| 1993 | 48.8 mm (1.9 in) |
| 1994 | 37.7 mm (1.5 in) |
| 1995 | 59.3 mm (2.3 in) |
| 1996 | 34.6 mm (1.4 in) |
| 1997 | 53.8 mm (2.1 in) |
| 1998 | 67.1 mm (2.6 in) |
| 1999 | 41.7 mm (1.6 in) |
| 2000 | 42.2 mm (1.7 in) |
| 2001 | 37.6 mm (1.5 in) |
| 2002 | 109.4 mm (4.3 in) |
| 2003 | 27.4 mm (1.1 in) |
| 2004 | 48.5 mm (1.9 in) |
| 2005 | 100.6 mm (4.0 in) |
| 2006 | 93.1 mm (3.7 in) |
| 2007 | 42.4 mm (1.7 in) |
| 2008 | 81.2 mm (3.2 in) |
| 2009 | 45.6 mm (1.8 in) |
| 2010 | 52.9 mm (2.1 in) |
| 2011 | 49.6 mm (2.0 in) |
| 2012 | 36.8 mm (1.4 in) |
| 2013 | 68.8 mm (2.7 in) |
| 2014 | 98.0 mm (3.9 in) |
| 2015 | 60.9 mm (2.4 in) |
| 2016 | 42.2 mm (1.7 in) |
| 2017 | 54.3 mm (2.1 in) |
| 2018 | 53.1 mm (2.1 in) |
| 2019 | 33.2 mm (1.3 in) |
| 2020 | 70.9 mm (2.8 in) |
| 2021 | 45.4 mm (1.8 in) |
| 2022 | 42.9 mm (1.7 in) |
| 2023 | 53.6 mm (2.1 in) |
| 2024 | 53.0 mm (2.1 in) |
| 2025 | 33.3 mm (1.3 in) |
| 2026 | 81.1 mm (3.2 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1937 | 41 days |
| 1938 | 39 days |
| 1939 | 43 days |
| 1940 | 34 days |
| 1941 | 22 days |
| 1942 | 30 days |
| 1943 | 24 days |
| 1944 | 34 days |
| 1945 | 37 days |
| 1946 | 38 days |
| 1947 | 21 days |
| 1948 | 30 days |
| 1949 | 41 days |
| 1950 | 37 days |
| 1951 | 28 days |
| 1952 | 33 days |
| 1953 | 48 days |
| 1954 | 69 days |
| 1955 | 45 days |
| 1956 | 20 days |
| 1957 | 42 days |
| 1958 | 20 days |
| 1959 | 43 days |
| 1960 | 47 days |
| 1961 | 28 days |
| 1962 | 35 days |
| 1963 | 27 days |
| 1964 | 73 days |
| 1965 | 48 days |
| 1966 | 26 days |
| 1967 | 33 days |
| 1968 | 35 days |
| 1969 | 72 days |
| 1970 | 29 days |
| 1971 | 30 days |
| 1972 | 27 days |
| 1973 | 34 days |
| 1974 | 39 days |
| 1975 | 18 days |
| 1976 | 50 days |
| 1977 | 39 days |
| 1978 | 19 days |
| 1979 | 26 days |
| 1980 | 27 days |
| 1981 | 35 days |
| 1982 | 28 days |
| 1983 | 32 days |
| 1984 | 40 days |
| 1985 | 26 days |
| 1986 | 29 days |
| 1987 | 35 days |
| 1988 | 30 days |
| 1989 | 17 days |
| 1990 | 40 days |
| 1991 | 29 days |
| 1992 | 24 days |
| 1993 | 21 days |
| 1994 | 39 days |
| 1995 | 40 days |
| 1996 | 22 days |
| 1997 | 30 days |
| 1998 | 31 days |
| 1999 | 35 days |
| 2000 | 22 days |
| 2001 | 31 days |
| 2002 | 28 days |
| 2003 | 37 days |
| 2004 | 48 days |
| 2005 | 63 days |
| 2006 | 26 days |
| 2007 | 32 days |
| 2008 | 24 days |
| 2009 | 34 days |
| 2010 | 27 days |
| 2011 | 20 days |
| 2012 | 47 days |
| 2013 | 21 days |
| 2014 | 22 days |
| 2015 | 27 days |
| 2016 | 42 days |
| 2017 | 59 days |
| 2018 | 28 days |
| 2019 | 26 days |
| 2020 | 38 days |
| 2021 | 38 days |
| 2022 | 17 days |
| 2023 | 24 days |
| 2024 | 35 days |
| 2025 | 19 days |
| 2026 | 26 days |
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
88 years with a frostAcross 88 years with a frost, the median last spring frost at Great Falls AP falls on 16 May and the median first autumn frost on 24 September, which leaves a median of 132 days between them.
In 1996 to 2025 the median growing season was 125 days. That is 21 days fewer than in 1938 to 1967.
Fitted over all years, the growing season changes by -2.5 days per decade at this station.
| Measure | Median, all years | Earliest period (1938 to 1967) | Recent period (1996 to 2025) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 16 May | 11 May | 22 May | 11 days later | +1.4 days per decade |
| First autumn frost | 24 September | 29 September | 22 September | 7 days earlier | -1.1 days per decade |
| Growing days | 132 days | 146 days | 125 days | 21 days fewer | -2.5 days per decade |
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
88 years, 1938 to 2025A day with at least 31.2 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 77.2 mm (3.0 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 31.2 mm (1.2 in) | |
| 5 years | 42.5 mm (1.7 in) | |
| 10 years | 50.4 mm (2.0 in) | |
| 25 years | 60.8 mm (2.4 in) | |
| 50 years | 68.9 mm (2.7 in) | |
| 100 years | 77.2 mm (3.0 in) | Longer than the 88 years of record |
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 88 years of values from 1938 to 2025.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 72.9 mm (2.9 in) in 2014; 63.5 mm (2.5 in) in 1980; 61.5 mm (2.4 in) in 2005.
Station Changes
1 suspectedOne change was suspected in the annual mean temperature of Great Falls AP, at 1966. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1966 ran 0.3 C (0.5 F) lower than in the years before (possible change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 1966 | -0.3 | -0.5 | possible | 5 |
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Climate Twins
2011 to 2025 against 1961 to 1990Over 2011 to 2025, Great Falls AP had a mean temperature of 7.4 C (45.2 F) and 376.8 mm (14.8 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Sybille Rsch Unit (United States, 793 km away), Black Mtn (United States, 510 km away) and Sunnyside (United States, 883 km away).
| Twin station | Country | Distance away | Mean temperature, 1961-1990 | Rain a year, 1961-1990 | Climate difference |
|---|---|---|---|---|---|
| Sybille Rsch Unit | United States | 793 km (493 mi) | 7.8 C (46.0 F) | 406.3 mm (16.0 in) | 1.06 |
| Black Mtn | United States | 510 km (317 mi) | 7.4 C (45.2 F) | 337.9 mm (13.3 in) | 1.12 |
| Sunnyside | United States | 883 km (549 mi) | 7.2 C (45.0 F) | 335.9 mm (13.2 in) | 1.16 |
Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.
Download the Data
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-16 (16 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-16).