Yellowstone Park Mammoth Weather Records (USC00489905)
Record envelope, standing records and threshold days for Yellowstone Park Mammoth (USC00489905), Wyoming, United States, with 133 years of record.
Key Facts for Yellowstone Park Mammoth
- Yellowstone Park Mammoth (USC00489905) is a weather station in Wyoming, United States at 44.98 latitude and -110.70 longitude, 1,891 m (6,203 ft) above sea level.
- The station reports from 1894 to 2026, 133 years of record.
- 1,464 records set at Yellowstone Park Mammoth still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Yellowstone Park Mammoth set a daily record high minimum temperature of 13.9 C (57.0 F) on 22 August 2026 (provisional).
Provisional Records
Records set in the last 60 days are provisional until they clear the revision window.
About the Station
- Location: Wyoming, United States, 44.98 latitude, -110.70 longitude.
- Elevation: 1,891 m (6,203 ft).
- Period of record: 1894 to 2026, 133 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
14 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 12.8 C (55.0 F) | -37.8 C (-36.0 F) | 8.3 C (46.9 F) | -24.4 C (-11.9 F) |
| Feb | 13.3 C (55.9 F) | -37.2 C (-35.0 F) | 11.7 C (53.1 F) | -19.4 C (-2.9 F) |
| Mar | 20.0 C (68.0 F) | -31.7 C (-25.1 F) | 20.0 C (68.0 F) | -13.9 C (7.0 F) |
| Apr | 25.6 C (78.1 F) | -21.1 C (-6.0 F) | 21.7 C (71.1 F) | -11.1 C (12.0 F) |
| May | 30.0 C (86.0 F) | -14.4 C (6.1 F) | 28.9 C (84.0 F) | -7.2 C (19.0 F) |
| Jun | 33.3 C (91.9 F) | -6.7 C (19.9 F) | 28.3 C (82.9 F) | -1.7 C (28.9 F) |
| Jul | 37.2 C (99.0 F) | -6.1 C (21.0 F) | 36.7 C (98.1 F) | 3.9 C (39.0 F) |
| Aug | 36.1 C (97.0 F) | -4.4 C (24.1 F) | 33.3 C (91.9 F) | 2.8 C (37.0 F) |
| Sep | 34.4 C (93.9 F) | -17.8 C (0.0 F) | n/a | n/a |
| Oct | 27.2 C (81.0 F) | -22.2 C (-8.0 F) | n/a | n/a |
| Nov | 18.9 C (66.0 F) | -32.8 C (-27.0 F) | n/a | n/a |
| Dec | 13.9 C (57.0 F) | -37.2 C (-35.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1894 | 26 |
| 1895 | 21 |
| 1896 | 30 |
| 1897 | 14 |
| 1898 | 13 |
| 1899 | 18 |
| 1900 | 24 |
| 1901 | 12 |
| 1902 | 12 |
| 1903 | 7 |
| 1941 | 10 |
| 1942 | 14 |
| 1943 | 13 |
| 1944 | 6 |
| 1945 | 10 |
| 1946 | 5 |
| 1947 | 13 |
| 1948 | 12 |
| 1949 | 19 |
| 1950 | 24 |
| 1951 | 16 |
| 1952 | 5 |
| 1953 | 14 |
| 1954 | 17 |
| 1955 | 15 |
| 1956 | 9 |
| 1957 | 9 |
| 1958 | 16 |
| 1959 | 22 |
| 1960 | 15 |
| 1961 | 13 |
| 1962 | 19 |
| 1963 | 18 |
| 1964 | 12 |
| 1965 | 26 |
| 1966 | 13 |
| 1967 | 8 |
| 1968 | 19 |
| 1969 | 15 |
| 1970 | 7 |
| 1971 | 9 |
| 1972 | 15 |
| 1973 | 13 |
| 1974 | 19 |
| 1975 | 18 |
| 1976 | 13 |
| 1977 | 1 |
| 1978 | 8 |
| 1979 | 11 |
| 1980 | 15 |
| 1981 | 10 |
| 1982 | 12 |
| 1983 | 11 |
| 1984 | 12 |
| 1985 | 19 |
| 1986 | 19 |
| 1987 | 30 |
| 1988 | 16 |
| 1989 | 19 |
| 1990 | 26 |
| 1991 | 14 |
| 1992 | 15 |
| 1993 | 16 |
| 1994 | 11 |
| 1995 | 10 |
| 1996 | 18 |
| 1997 | 14 |
| 1998 | 13 |
| 1999 | 15 |
| 2000 | 13 |
| 2001 | 17 |
| 2002 | 16 |
| 2003 | 30 |
| 2004 | 7 |
| 2005 | 17 |
| 2006 | 17 |
| 2007 | 20 |
| 2008 | 24 |
| 2009 | 14 |
| 2010 | 9 |
| 2011 | 10 |
| 2012 | 19 |
| 2013 | 12 |
| 2014 | 19 |
| 2015 | 22 |
| 2016 | 26 |
| 2017 | 12 |
| 2018 | 7 |
| 2019 | 22 |
| 2020 | 16 |
| 2021 | 18 |
| 2022 | 26 |
| 2023 | 13 |
| 2024 | 18 |
| 2025 | 14 |
| 2026 | 13 |
All-Time Record Progression
8 new records| Date | Kind | Detail |
|---|---|---|
| 1963-01-11 | Record low maximum temperature | Record low maximum temperature -28.9 C (-20.0 F) |
| 1979-03-01 | Record daily snowfall | Record daily snowfall 45.7 cm (18.0 in) |
| 1982-08-30 | Record daily precipitation | Record daily precipitation 57.2 mm (2.3 in) |
| 1989-02-03 | Record low maximum temperature | Record low maximum temperature -30.6 C (-23.1 F) |
| 1989-02-04 | Record low maximum temperature | Record low maximum temperature -32.2 C (-26.0 F) |
| 2002-07-13 | Record high maximum temperature | Record high maximum temperature 36.7 C (98.1 F) |
| 2002-07-14 | Record high maximum temperature | Record high maximum temperature 37.2 C (99.0 F) |
| 2022-06-13 | Record daily precipitation | Record daily precipitation 57.9 mm (2.3 in) |
Wettest Day of Each Month
Jun: 57.9 mm (2.3 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 40.6 mm (1.6 in) | 17 January 1895 |
| Feb | 20.3 mm (0.8 in) | 16 February 1898 |
| Mar | 29.7 mm (1.2 in) | 2 March 1974 |
| Apr | 22.1 mm (0.9 in) | 22 April 1958 |
| May | 47.2 mm (1.9 in) | 7 May 1988 |
| Jun | 57.9 mm (2.3 in) | 13 June 2022 |
| Jul | 49.0 mm (1.9 in) | 18 July 2026 |
| Aug | 57.2 mm (2.3 in) | 30 August 1982 |
| Sep | 31.8 mm (1.3 in) | 11 September 1961 |
| Oct | 29.5 mm (1.2 in) | 7 October 1981 |
| Nov | 46.7 mm (1.8 in) | 20 November 2010 |
| Dec | 43.2 mm (1.7 in) | 23 December 1955 |
Period of Record Coverage
1894 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1894 | 268 | 73% | No |
| 1895 | 292 | 80% | No |
| 1896 | 362 | 99% | Yes |
| 1897 | 329 | 90% | Yes |
| 1898 | 354 | 97% | Yes |
| 1899 | 362 | 99% | Yes |
| 1900 | 340 | 93% | Yes |
| 1901 | 353 | 97% | Yes |
| 1902 | 357 | 98% | Yes |
| 1903 | 356 | 98% | Yes |
| 1941 | 213 | 58% | No |
| 1942 | 358 | 98% | Yes |
| 1943 | 331 | 91% | Yes |
| 1944 | 366 | 100% | Yes |
| 1945 | 365 | 100% | Yes |
| 1946 | 364 | 100% | Yes |
| 1947 | 364 | 100% | Yes |
| 1948 | 359 | 98% | Yes |
| 1949 | 361 | 99% | Yes |
| 1950 | 365 | 100% | Yes |
| 1951 | 360 | 99% | Yes |
| 1952 | 359 | 98% | Yes |
| 1953 | 331 | 91% | Yes |
| 1954 | 358 | 98% | Yes |
| 1955 | 365 | 100% | Yes |
| 1956 | 364 | 99% | Yes |
| 1957 | 364 | 100% | Yes |
| 1958 | 363 | 99% | Yes |
| 1959 | 363 | 99% | Yes |
| 1960 | 365 | 100% | Yes |
| 1961 | 334 | 92% | Yes |
| 1962 | 357 | 98% | Yes |
| 1963 | 353 | 97% | Yes |
| 1964 | 350 | 96% | Yes |
| 1965 | 338 | 93% | Yes |
| 1966 | 226 | 62% | No |
| 1967 | 311 | 85% | No |
| 1968 | 360 | 98% | Yes |
| 1969 | 358 | 98% | Yes |
| 1970 | 358 | 98% | Yes |
| 1971 | 324 | 89% | No |
| 1972 | 359 | 98% | Yes |
| 1973 | 330 | 90% | Yes |
| 1974 | 356 | 98% | Yes |
| 1975 | 361 | 99% | Yes |
| 1976 | 354 | 97% | Yes |
| 1977 | 153 | 42% | No |
| 1978 | 204 | 56% | No |
| 1979 | 349 | 96% | Yes |
| 1980 | 336 | 92% | Yes |
| 1981 | 221 | 61% | No |
| 1982 | 283 | 78% | No |
| 1983 | 275 | 75% | No |
| 1984 | 267 | 73% | No |
| 1985 | 317 | 87% | No |
| 1986 | 362 | 99% | Yes |
| 1987 | 364 | 100% | Yes |
| 1988 | 366 | 100% | Yes |
| 1989 | 364 | 100% | Yes |
| 1990 | 362 | 99% | Yes |
| 1991 | 363 | 99% | Yes |
| 1992 | 365 | 100% | Yes |
| 1993 | 365 | 100% | Yes |
| 1994 | 360 | 99% | Yes |
| 1995 | 361 | 99% | Yes |
| 1996 | 363 | 99% | Yes |
| 1997 | 365 | 100% | Yes |
| 1998 | 364 | 100% | Yes |
| 1999 | 365 | 100% | Yes |
| 2000 | 360 | 98% | Yes |
| 2001 | 362 | 99% | Yes |
| 2002 | 361 | 99% | Yes |
| 2003 | 334 | 92% | Yes |
| 2004 | 365 | 100% | Yes |
| 2005 | 365 | 100% | Yes |
| 2006 | 335 | 92% | Yes |
| 2007 | 355 | 97% | Yes |
| 2008 | 347 | 95% | Yes |
| 2009 | 363 | 99% | Yes |
| 2010 | 356 | 98% | Yes |
| 2011 | 365 | 100% | Yes |
| 2012 | 366 | 100% | Yes |
| 2013 | 365 | 100% | Yes |
| 2014 | 364 | 100% | Yes |
| 2015 | 365 | 100% | Yes |
| 2016 | 366 | 100% | Yes |
| 2017 | 355 | 97% | Yes |
| 2018 | 360 | 99% | Yes |
| 2019 | 348 | 95% | Yes |
| 2020 | 363 | 99% | Yes |
| 2021 | 353 | 97% | Yes |
| 2022 | 363 | 99% | Yes |
| 2023 | 354 | 97% | Yes |
| 2024 | 354 | 97% | Yes |
| 2025 | 313 | 86% | No |
| 2026 | 237 | 65% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 22 August 2026 | Yellowstone Park Mammoth, US | daily high min (Provisional) | 13.9 C (57.0 F) | 0.6 C (1.1 F) | 131 years | 41 of 100 (Notable) |
| 21 August 2026 | Yellowstone Park Mammoth, US | daily high max (Tie, Provisional) | 32.2 C (90.0 F) | tie | 7 years | 3 of 100 (Routine) |
| 18 July 2026 | Yellowstone Park Mammoth, US | monthly rain | 49.0 mm (1.9 in) | 13.4 mm (0.5 in) | 124 years | 79 of 100 (Major) |
| 13 July 2026 | Yellowstone Park Mammoth, US | daily high max (Tie) | 36.7 C (98.1 F) | tie | 24 years | 4 of 100 (Routine) |
| 30 June 2026 | Yellowstone Park Mammoth, US | daily low max (Tie) | 12.2 C (54.0 F) | tie | 5 years | 2 of 100 (Routine) |
| 17 June 2026 | Yellowstone Park Mammoth, US | daily high min | 11.1 C (52.0 F) | 1.1 C (2.0 F) | 40 years | 25 of 100 (Routine) |
| 11 June 2026 | Yellowstone Park Mammoth, US | daily low min | -1.7 C (28.9 F) | 0.6 C (1.1 F) | 48 years | 25 of 100 (Routine) |
| 9 June 2026 | Yellowstone Park Mammoth, US | daily low min (Tie) | -1.7 C (28.9 F) | tie | 130 years | 10 of 100 (Routine) |
| 22 May 2026 | Yellowstone Park Mammoth, US | daily low min | -6.1 C (21.0 F) | 0.5 C (0.9 F) | 4 years | 12 of 100 (Routine) |
| 14 May 2026 | Yellowstone Park Mammoth, US | daily high max | 27.2 C (81.0 F) | 0.5 C (0.9 F) | 19 years | 15 of 100 (Routine) |
| 25 April 2026 | Yellowstone Park Mammoth, US | daily low max | 0.0 C (32.0 F) | 0.6 C (1.1 F) | 16 years | 16 of 100 (Routine) |
| 29 March 2026 | Yellowstone Park Mammoth, US | monthly high max | 20.0 C (68.0 F) | 0.6 C (1.1 F) | 0 years | 21 of 100 (Routine) |
| 25 March 2026 | Yellowstone Park Mammoth, US | monthly high min | 6.7 C (44.1 F) | 0.6 C (1.1 F) | 0 years | 20 of 100 (Routine) |
| 25 March 2026 | Yellowstone Park Mammoth, US | daily high max (Tie) | 16.7 C (62.1 F) | tie | 19 years | 3 of 100 (Routine) |
| 22 March 2026 | Yellowstone Park Mammoth, US | daily high max (Tie) | 17.8 C (64.0 F) | tie | 53 years | 6 of 100 (Routine) |
| 21 March 2026 | Yellowstone Park Mammoth, US | monthly high max (Tie) | 19.4 C (66.9 F) | tie | 0 years | 5 of 100 (Routine) |
| 21 March 2026 | Yellowstone Park Mammoth, US | monthly high min (Tie) | 6.1 C (43.0 F) | tie | 0 years | 5 of 100 (Routine) |
| 20 March 2026 | Yellowstone Park Mammoth, US | monthly high min | 6.1 C (43.0 F) | 0.5 C (0.9 F) | 39 years | 31 of 100 (Routine) |
| 20 March 2026 | Yellowstone Park Mammoth, US | monthly high max | 19.4 C (66.9 F) | 0.5 C (0.9 F) | 27 years | 28 of 100 (Routine) |
| 19 March 2026 | Yellowstone Park Mammoth, US | daily high max (Tie) | 17.8 C (64.0 F) | tie | 8 years | 3 of 100 (Routine) |
Climate Trend
73 complete years, 1896 to 2024| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1896 | 3.9 C | -0.74 C |
| 1898 | 3.4 C | -1.26 C |
| 1899 | 3.1 C | -1.55 C |
| 1901 | 4.7 C | +0.04 C |
| 1902 | 4.1 C | -0.51 C |
| 1903 | 4.2 C | -0.40 C |
| 1942 | 4.3 C | -0.37 C |
| 1944 | 4.3 C | -0.33 C |
| 1945 | 4.3 C | -0.33 C |
| 1946 | 4.4 C | -0.22 C |
| 1947 | 3.2 C | -1.41 C |
| 1948 | 2.4 C | -2.21 C |
| 1949 | 3.8 C | -0.79 C |
| 1950 | 4.0 C | -0.62 C |
| 1951 | 3.3 C | -1.38 C |
| 1952 | 4.5 C | -0.10 C |
| 1954 | 5.0 C | +0.35 C |
| 1955 | 3.4 C | -1.25 C |
| 1956 | 4.3 C | -0.30 C |
| 1957 | 4.2 C | -0.48 C |
| 1958 | 5.5 C | +0.87 C |
| 1959 | 3.8 C | -0.88 C |
| 1960 | 4.4 C | -0.27 C |
| 1962 | 4.6 C | -0.05 C |
| 1963 | 5.2 C | +0.57 C |
| 1964 | 4.0 C | -0.64 C |
| 1965 | 4.0 C | -0.60 C |
| 1968 | 4.5 C | -0.13 C |
| 1969 | 5.2 C | +0.56 C |
| 1970 | 4.4 C | -0.26 C |
| 1972 | 4.6 C | -0.05 C |
| 1974 | 4.6 C | -0.04 C |
| 1975 | 3.4 C | -1.27 C |
| 1976 | 5.0 C | +0.40 C |
| 1979 | 4.4 C | -0.24 C |
| 1980 | 4.9 C | +0.25 C |
| 1986 | 5.4 C | +0.79 C |
| 1987 | 5.5 C | +0.86 C |
| 1988 | 5.3 C | +0.68 C |
| 1989 | 4.2 C | -0.42 C |
| 1990 | 4.8 C | +0.13 C |
| 1991 | 5.0 C | +0.37 C |
| 1992 | 5.5 C | +0.87 C |
| 1993 | 3.6 C | -0.99 C |
| 1994 | 5.6 C | +0.97 C |
| 1995 | 4.7 C | +0.08 C |
| 1996 | 4.5 C | -0.12 C |
| 1997 | 4.2 C | -0.40 C |
| 1998 | 5.4 C | +0.75 C |
| 1999 | 5.2 C | +0.60 C |
| 2000 | 4.9 C | +0.26 C |
| 2001 | 5.3 C | +0.67 C |
| 2002 | 3.8 C | -0.88 C |
| 2004 | 5.2 C | +0.56 C |
| 2005 | 5.9 C | +1.24 C |
| 2007 | 6.2 C | +1.53 C |
| 2008 | 4.1 C | -0.51 C |
| 2009 | 4.0 C | -0.59 C |
| 2010 | 5.0 C | +0.41 C |
| 2011 | 4.6 C | -0.07 C |
| 2012 | 6.2 C | +1.61 C |
| 2013 | 5.1 C | +0.45 C |
| 2014 | 5.3 C | +0.62 C |
| 2015 | 6.5 C | +1.86 C |
| 2016 | 6.7 C | +2.08 C |
| 2017 | 5.5 C | +0.85 C |
| 2018 | 5.0 C | +0.36 C |
| 2019 | 4.0 C | -0.68 C |
| 2020 | 5.2 C | +0.53 C |
| 2021 | 5.4 C | +0.72 C |
| 2022 | 4.0 C | -0.60 C |
| 2023 | 4.9 C | +0.22 C |
| 2024 | 5.8 C | +1.19 C |
The annual mean temperature here has risen by 0.1 C (0.1 to 0.2) per decade over 1896 to 2024. In Fahrenheit: 0.2 F (0.2 to 0.3) per decade. The slope is a straight line fitted to 73 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.1 C (0.1 to 0.2) per decade | 0.2 F (0.2 to 0.3) per decade | 1896 to 2024 | 73 | Rise |
| Mean daily maximum | 0.1 C (0.1 to 0.2) per decade | 0.3 F (0.2 to 0.4) per decade | 1896 to 2024 | 73 | Rise |
| Mean daily minimum | 0.1 C (0.1 to 0.2) per decade | 0.2 F (0.1 to 0.3) per decade | 1896 to 2024 | 73 | Rise |
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
1894 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 37.2 C (99.0 F) | 2002 | 32.8 C (91.0 F) | 96 |
| Coldest night (TNn) | -37.8 C (-36.0 F) | 1951 | -29.4 C (-20.9 F) | 96 |
| Wettest day (Rx1day) | 57.9 mm (2.3 in) | 2022 | 21.4 mm (0.8 in) | 96 |
| Wettest five days (Rx5day) | 73.1 mm (2.9 in) | 2010 | 38.2 mm (1.5 in) | 96 |
| Longest dry spell (CDD) | 64 days | 1952 | 25 days | 96 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1894 | 32.2 C (90.0 F) |
| 1895 | 30.6 C (87.1 F) |
| 1896 | 31.1 C (88.0 F) |
| 1897 | 31.7 C (89.1 F) |
| 1898 | 31.7 C (89.1 F) |
| 1899 | 31.1 C (88.0 F) |
| 1900 | 33.9 C (93.0 F) |
| 1901 | 35.6 C (96.1 F) |
| 1902 | 30.0 C (86.0 F) |
| 1903 | 32.2 C (90.0 F) |
| 1941 | 32.8 C (91.0 F) |
| 1942 | 32.8 C (91.0 F) |
| 1943 | 32.8 C (91.0 F) |
| 1944 | 28.9 C (84.0 F) |
| 1945 | 31.7 C (89.1 F) |
| 1946 | 32.8 C (91.0 F) |
| 1947 | 31.7 C (89.1 F) |
| 1948 | 30.0 C (86.0 F) |
| 1949 | 35.0 C (95.0 F) |
| 1950 | 33.3 C (91.9 F) |
| 1951 | 31.7 C (89.1 F) |
| 1952 | 32.8 C (91.0 F) |
| 1953 | 31.7 C (89.1 F) |
| 1954 | 34.4 C (93.9 F) |
| 1955 | 34.4 C (93.9 F) |
| 1956 | 32.2 C (90.0 F) |
| 1957 | 31.1 C (88.0 F) |
| 1958 | 32.2 C (90.0 F) |
| 1959 | 33.3 C (91.9 F) |
| 1960 | 35.0 C (95.0 F) |
| 1961 | 34.4 C (93.9 F) |
| 1962 | 32.8 C (91.0 F) |
| 1963 | 32.8 C (91.0 F) |
| 1964 | 31.7 C (89.1 F) |
| 1965 | 31.7 C (89.1 F) |
| 1966 | 33.3 C (91.9 F) |
| 1967 | 35.0 C (95.0 F) |
| 1968 | 31.7 C (89.1 F) |
| 1969 | 32.8 C (91.0 F) |
| 1970 | 32.2 C (90.0 F) |
| 1971 | 32.2 C (90.0 F) |
| 1972 | 32.2 C (90.0 F) |
| 1973 | 33.9 C (93.0 F) |
| 1974 | 33.3 C (91.9 F) |
| 1975 | 32.2 C (90.0 F) |
| 1976 | 33.9 C (93.0 F) |
| 1977 | 22.2 C (72.0 F) |
| 1978 | 31.7 C (89.1 F) |
| 1979 | 33.9 C (93.0 F) |
| 1980 | 32.2 C (90.0 F) |
| 1981 | 25.6 C (78.1 F) |
| 1982 | 31.7 C (89.1 F) |
| 1983 | 32.2 C (90.0 F) |
| 1984 | 31.7 C (89.1 F) |
| 1985 | 32.8 C (91.0 F) |
| 1986 | 32.2 C (90.0 F) |
| 1987 | 31.1 C (88.0 F) |
| 1988 | 33.9 C (93.0 F) |
| 1989 | 32.8 C (91.0 F) |
| 1990 | 33.3 C (91.9 F) |
| 1991 | 33.3 C (91.9 F) |
| 1992 | 31.7 C (89.1 F) |
| 1993 | 27.8 C (82.0 F) |
| 1994 | 32.8 C (91.0 F) |
| 1995 | 32.2 C (90.0 F) |
| 1996 | 34.4 C (93.9 F) |
| 1997 | 32.2 C (90.0 F) |
| 1998 | 34.4 C (93.9 F) |
| 1999 | 33.3 C (91.9 F) |
| 2000 | 35.6 C (96.1 F) |
| 2001 | 34.4 C (93.9 F) |
| 2002 | 37.2 C (99.0 F) |
| 2003 | 36.1 C (97.0 F) |
| 2004 | 32.8 C (91.0 F) |
| 2005 | 33.9 C (93.0 F) |
| 2006 | 35.6 C (96.1 F) |
| 2007 | 36.1 C (97.0 F) |
| 2008 | 31.7 C (89.1 F) |
| 2009 | 32.2 C (90.0 F) |
| 2010 | 34.4 C (93.9 F) |
| 2011 | 32.2 C (90.0 F) |
| 2012 | 33.3 C (91.9 F) |
| 2013 | 32.8 C (91.0 F) |
| 2014 | 31.1 C (88.0 F) |
| 2015 | 33.3 C (91.9 F) |
| 2016 | 32.8 C (91.0 F) |
| 2017 | 33.9 C (93.0 F) |
| 2018 | 35.6 C (96.1 F) |
| 2019 | 33.3 C (91.9 F) |
| 2020 | 34.4 C (93.9 F) |
| 2021 | 35.6 C (96.1 F) |
| 2022 | 34.4 C (93.9 F) |
| 2023 | 35.0 C (95.0 F) |
| 2024 | 35.6 C (96.1 F) |
| 2025 | 32.8 C (91.0 F) |
| 2026 | 36.7 C (98.1 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1894 | -31.7 C (-25.1 F) |
| 1895 | -32.2 C (-26.0 F) |
| 1896 | -32.8 C (-27.0 F) |
| 1897 | -28.3 C (-18.9 F) |
| 1898 | -30.0 C (-22.0 F) |
| 1899 | -37.2 C (-35.0 F) |
| 1900 | -31.7 C (-25.1 F) |
| 1901 | -26.1 C (-15.0 F) |
| 1902 | -34.4 C (-29.9 F) |
| 1903 | -28.9 C (-20.0 F) |
| 1941 | -25.6 C (-14.1 F) |
| 1942 | -33.3 C (-27.9 F) |
| 1943 | -28.3 C (-18.9 F) |
| 1944 | -27.8 C (-18.0 F) |
| 1945 | -26.1 C (-15.0 F) |
| 1946 | -24.4 C (-11.9 F) |
| 1947 | -30.6 C (-23.1 F) |
| 1948 | -32.2 C (-26.0 F) |
| 1949 | -34.4 C (-29.9 F) |
| 1950 | -31.1 C (-24.0 F) |
| 1951 | -37.8 C (-36.0 F) |
| 1952 | -28.3 C (-18.9 F) |
| 1953 | -23.9 C (-11.0 F) |
| 1954 | -27.8 C (-18.0 F) |
| 1955 | -29.4 C (-20.9 F) |
| 1956 | -32.8 C (-27.0 F) |
| 1957 | -31.7 C (-25.1 F) |
| 1958 | -19.4 C (-2.9 F) |
| 1959 | -33.9 C (-29.0 F) |
| 1960 | -30.6 C (-23.1 F) |
| 1961 | -30.0 C (-22.0 F) |
| 1962 | -34.4 C (-29.9 F) |
| 1963 | -37.8 C (-36.0 F) |
| 1964 | -36.7 C (-34.1 F) |
| 1965 | -31.1 C (-24.0 F) |
| 1966 | -28.9 C (-20.0 F) |
| 1967 | -27.8 C (-18.0 F) |
| 1968 | -27.8 C (-18.0 F) |
| 1969 | -26.7 C (-16.1 F) |
| 1970 | -29.4 C (-20.9 F) |
| 1971 | -27.8 C (-18.0 F) |
| 1972 | -32.8 C (-27.0 F) |
| 1973 | -30.0 C (-22.0 F) |
| 1974 | -27.8 C (-18.0 F) |
| 1975 | -27.8 C (-18.0 F) |
| 1976 | -27.2 C (-17.0 F) |
| 1977 | -25.6 C (-14.1 F) |
| 1978 | -35.0 C (-31.0 F) |
| 1979 | -30.6 C (-23.1 F) |
| 1980 | -33.3 C (-27.9 F) |
| 1981 | -33.9 C (-29.0 F) |
| 1982 | -32.8 C (-27.0 F) |
| 1983 | -33.3 C (-27.9 F) |
| 1984 | -28.9 C (-20.0 F) |
| 1985 | -31.7 C (-25.1 F) |
| 1986 | -26.7 C (-16.1 F) |
| 1987 | -26.7 C (-16.1 F) |
| 1988 | -26.1 C (-15.0 F) |
| 1989 | -37.2 C (-35.0 F) |
| 1990 | -37.2 C (-35.0 F) |
| 1991 | -28.9 C (-20.0 F) |
| 1992 | -26.1 C (-15.0 F) |
| 1993 | -27.2 C (-17.0 F) |
| 1994 | -26.1 C (-15.0 F) |
| 1995 | -26.1 C (-15.0 F) |
| 1996 | -31.1 C (-24.0 F) |
| 1997 | -34.4 C (-29.9 F) |
| 1998 | -32.2 C (-26.0 F) |
| 1999 | -18.9 C (-2.0 F) |
| 2000 | -25.0 C (-13.0 F) |
| 2001 | -27.8 C (-18.0 F) |
| 2002 | -26.1 C (-15.0 F) |
| 2003 | -31.1 C (-24.0 F) |
| 2004 | -30.6 C (-23.1 F) |
| 2005 | -27.8 C (-18.0 F) |
| 2006 | -21.7 C (-7.1 F) |
| 2007 | -31.7 C (-25.1 F) |
| 2008 | -27.8 C (-18.0 F) |
| 2009 | -26.1 C (-15.0 F) |
| 2010 | -26.7 C (-16.1 F) |
| 2011 | -27.8 C (-18.0 F) |
| 2012 | -21.1 C (-6.0 F) |
| 2013 | -29.4 C (-20.9 F) |
| 2014 | -33.9 C (-29.0 F) |
| 2015 | -23.3 C (-9.9 F) |
| 2016 | -31.1 C (-24.0 F) |
| 2017 | -28.9 C (-20.0 F) |
| 2018 | -28.9 C (-20.0 F) |
| 2019 | -32.2 C (-26.0 F) |
| 2020 | -23.3 C (-9.9 F) |
| 2021 | -28.9 C (-20.0 F) |
| 2022 | -36.1 C (-33.0 F) |
| 2023 | -32.8 C (-27.0 F) |
| 2024 | -35.0 C (-31.0 F) |
| 2025 | -31.1 C (-24.0 F) |
| 2026 | -24.4 C (-11.9 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1894 | 30.5 mm (1.2 in) |
| 1895 | 40.6 mm (1.6 in) |
| 1896 | 20.3 mm (0.8 in) |
| 1897 | 25.4 mm (1.0 in) |
| 1898 | 20.3 mm (0.8 in) |
| 1899 | 35.6 mm (1.4 in) |
| 1900 | 25.4 mm (1.0 in) |
| 1901 | 22.9 mm (0.9 in) |
| 1902 | 35.6 mm (1.4 in) |
| 1903 | 12.7 mm (0.5 in) |
| 1941 | 38.9 mm (1.5 in) |
| 1942 | 16.5 mm (0.6 in) |
| 1943 | 18.5 mm (0.7 in) |
| 1944 | 27.4 mm (1.1 in) |
| 1945 | 30.2 mm (1.2 in) |
| 1946 | 21.6 mm (0.9 in) |
| 1947 | 36.3 mm (1.4 in) |
| 1948 | 19.8 mm (0.8 in) |
| 1949 | 18.8 mm (0.7 in) |
| 1950 | 20.8 mm (0.8 in) |
| 1951 | 20.6 mm (0.8 in) |
| 1952 | 23.4 mm (0.9 in) |
| 1953 | 21.8 mm (0.9 in) |
| 1954 | 19.6 mm (0.8 in) |
| 1955 | 43.2 mm (1.7 in) |
| 1956 | 19.1 mm (0.8 in) |
| 1957 | 14.0 mm (0.6 in) |
| 1958 | 22.1 mm (0.9 in) |
| 1959 | 14.7 mm (0.6 in) |
| 1960 | 30.5 mm (1.2 in) |
| 1961 | 31.8 mm (1.3 in) |
| 1962 | 19.6 mm (0.8 in) |
| 1963 | 15.7 mm (0.6 in) |
| 1964 | 33.5 mm (1.3 in) |
| 1965 | 16.8 mm (0.7 in) |
| 1966 | 20.3 mm (0.8 in) |
| 1967 | 27.7 mm (1.1 in) |
| 1968 | 23.9 mm (0.9 in) |
| 1969 | 17.8 mm (0.7 in) |
| 1970 | 16.0 mm (0.6 in) |
| 1971 | 19.3 mm (0.8 in) |
| 1972 | 23.1 mm (0.9 in) |
| 1973 | 15.2 mm (0.6 in) |
| 1974 | 29.7 mm (1.2 in) |
| 1975 | 19.6 mm (0.8 in) |
| 1976 | 38.1 mm (1.5 in) |
| 1977 | 8.9 mm (0.35 in) |
| 1978 | 15.7 mm (0.6 in) |
| 1979 | 22.9 mm (0.9 in) |
| 1980 | 19.1 mm (0.8 in) |
| 1981 | 29.5 mm (1.2 in) |
| 1982 | 57.2 mm (2.3 in) |
| 1983 | 30.7 mm (1.2 in) |
| 1984 | 17.8 mm (0.7 in) |
| 1985 | 16.5 mm (0.6 in) |
| 1986 | 17.8 mm (0.7 in) |
| 1987 | 30.0 mm (1.2 in) |
| 1988 | 47.2 mm (1.9 in) |
| 1989 | 20.3 mm (0.8 in) |
| 1990 | 23.9 mm (0.9 in) |
| 1991 | 23.1 mm (0.9 in) |
| 1992 | 29.2 mm (1.1 in) |
| 1993 | 30.0 mm (1.2 in) |
| 1994 | 19.8 mm (0.8 in) |
| 1995 | 16.5 mm (0.6 in) |
| 1996 | 19.8 mm (0.8 in) |
| 1997 | 22.1 mm (0.9 in) |
| 1998 | 24.1 mm (0.9 in) |
| 1999 | 21.1 mm (0.8 in) |
| 2000 | 17.3 mm (0.7 in) |
| 2001 | 14.0 mm (0.6 in) |
| 2002 | 17.8 mm (0.7 in) |
| 2003 | 20.8 mm (0.8 in) |
| 2004 | 18.5 mm (0.7 in) |
| 2005 | 20.3 mm (0.8 in) |
| 2006 | 23.9 mm (0.9 in) |
| 2007 | 28.4 mm (1.1 in) |
| 2008 | 33.0 mm (1.3 in) |
| 2009 | 20.1 mm (0.8 in) |
| 2010 | 46.7 mm (1.8 in) |
| 2011 | 15.2 mm (0.6 in) |
| 2012 | 17.8 mm (0.7 in) |
| 2013 | 18.3 mm (0.7 in) |
| 2014 | 18.0 mm (0.7 in) |
| 2015 | 25.9 mm (1.0 in) |
| 2016 | 27.9 mm (1.1 in) |
| 2017 | 25.7 mm (1.0 in) |
| 2018 | 29.5 mm (1.2 in) |
| 2019 | 19.1 mm (0.8 in) |
| 2020 | 22.9 mm (0.9 in) |
| 2021 | 19.6 mm (0.8 in) |
| 2022 | 57.9 mm (2.3 in) |
| 2023 | 24.4 mm (1.0 in) |
| 2024 | 16.3 mm (0.6 in) |
| 2025 | 18.0 mm (0.7 in) |
| 2026 | 49.0 mm (1.9 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1894 | 35.9 mm (1.4 in) |
| 1895 | 61.3 mm (2.4 in) |
| 1896 | 48.9 mm (1.9 in) |
| 1897 | 40.6 mm (1.6 in) |
| 1898 | 31.7 mm (1.2 in) |
| 1899 | 38.1 mm (1.5 in) |
| 1900 | 46.9 mm (1.8 in) |
| 1901 | 38.2 mm (1.5 in) |
| 1902 | 54.6 mm (2.1 in) |
| 1903 | 19.0 mm (0.7 in) |
| 1941 | 56.0 mm (2.2 in) |
| 1942 | 32.5 mm (1.3 in) |
| 1943 | 33.6 mm (1.3 in) |
| 1944 | 54.4 mm (2.1 in) |
| 1945 | 56.6 mm (2.2 in) |
| 1946 | 47.8 mm (1.9 in) |
| 1947 | 41.6 mm (1.6 in) |
| 1948 | 42.1 mm (1.7 in) |
| 1949 | 29.3 mm (1.2 in) |
| 1950 | 27.9 mm (1.1 in) |
| 1951 | 28.8 mm (1.1 in) |
| 1952 | 50.6 mm (2.0 in) |
| 1953 | 34.0 mm (1.3 in) |
| 1954 | 40.2 mm (1.6 in) |
| 1955 | 72.1 mm (2.8 in) |
| 1956 | 36.1 mm (1.4 in) |
| 1957 | 25.8 mm (1.0 in) |
| 1958 | 48.8 mm (1.9 in) |
| 1959 | 36.1 mm (1.4 in) |
| 1960 | 31.8 mm (1.3 in) |
| 1961 | 48.8 mm (1.9 in) |
| 1962 | 30.8 mm (1.2 in) |
| 1963 | 37.3 mm (1.5 in) |
| 1964 | 45.7 mm (1.8 in) |
| 1965 | 26.0 mm (1.0 in) |
| 1966 | 23.6 mm (0.9 in) |
| 1967 | 37.8 mm (1.5 in) |
| 1968 | 55.1 mm (2.2 in) |
| 1969 | 58.5 mm (2.3 in) |
| 1970 | 31.0 mm (1.2 in) |
| 1971 | 36.0 mm (1.4 in) |
| 1972 | 41.2 mm (1.6 in) |
| 1973 | 27.4 mm (1.1 in) |
| 1974 | 44.2 mm (1.7 in) |
| 1975 | 23.8 mm (0.9 in) |
| 1976 | 53.7 mm (2.1 in) |
| 1977 | 14.7 mm (0.6 in) |
| 1978 | 25.4 mm (1.0 in) |
| 1979 | 32.1 mm (1.3 in) |
| 1980 | 33.8 mm (1.3 in) |
| 1981 | 29.8 mm (1.2 in) |
| 1982 | 70.9 mm (2.8 in) |
| 1983 | 35.6 mm (1.4 in) |
| 1984 | 40.2 mm (1.6 in) |
| 1985 | 24.6 mm (1.0 in) |
| 1986 | 28.2 mm (1.1 in) |
| 1987 | 45.5 mm (1.8 in) |
| 1988 | 61.7 mm (2.4 in) |
| 1989 | 37.0 mm (1.5 in) |
| 1990 | 32.4 mm (1.3 in) |
| 1991 | 64.5 mm (2.5 in) |
| 1992 | 63.5 mm (2.5 in) |
| 1993 | 45.2 mm (1.8 in) |
| 1994 | 32.5 mm (1.3 in) |
| 1995 | 26.9 mm (1.1 in) |
| 1996 | 36.7 mm (1.4 in) |
| 1997 | 38.3 mm (1.5 in) |
| 1998 | 44.9 mm (1.8 in) |
| 1999 | 38.7 mm (1.5 in) |
| 2000 | 28.1 mm (1.1 in) |
| 2001 | 28.0 mm (1.1 in) |
| 2002 | 32.8 mm (1.3 in) |
| 2003 | 25.1 mm (1.0 in) |
| 2004 | 32.0 mm (1.3 in) |
| 2005 | 29.7 mm (1.2 in) |
| 2006 | 34.1 mm (1.3 in) |
| 2007 | 42.5 mm (1.7 in) |
| 2008 | 44.4 mm (1.7 in) |
| 2009 | 27.7 mm (1.1 in) |
| 2010 | 73.1 mm (2.9 in) |
| 2011 | 31.8 mm (1.3 in) |
| 2012 | 32.6 mm (1.3 in) |
| 2013 | 39.9 mm (1.6 in) |
| 2014 | 38.7 mm (1.5 in) |
| 2015 | 46.5 mm (1.8 in) |
| 2016 | 39.6 mm (1.6 in) |
| 2017 | 65.8 mm (2.6 in) |
| 2018 | 54.6 mm (2.1 in) |
| 2019 | 46.9 mm (1.8 in) |
| 2020 | 48.6 mm (1.9 in) |
| 2021 | 44.5 mm (1.8 in) |
| 2022 | 67.7 mm (2.7 in) |
| 2023 | 39.9 mm (1.6 in) |
| 2024 | 27.7 mm (1.1 in) |
| 2025 | 34.3 mm (1.4 in) |
| 2026 | 56.6 mm (2.2 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1894 | 18 days |
| 1895 | 34 days |
| 1896 | 20 days |
| 1897 | 48 days |
| 1898 | 22 days |
| 1899 | 30 days |
| 1900 | 22 days |
| 1901 | 18 days |
| 1902 | 25 days |
| 1903 | 34 days |
| 1941 | 20 days |
| 1942 | 16 days |
| 1943 | 23 days |
| 1944 | 36 days |
| 1945 | 21 days |
| 1946 | 17 days |
| 1947 | 16 days |
| 1948 | 36 days |
| 1949 | 17 days |
| 1950 | 22 days |
| 1951 | 15 days |
| 1952 | 64 days |
| 1953 | 50 days |
| 1954 | 23 days |
| 1955 | 36 days |
| 1956 | 22 days |
| 1957 | 22 days |
| 1958 | 21 days |
| 1959 | 25 days |
| 1960 | 22 days |
| 1961 | 29 days |
| 1962 | 25 days |
| 1963 | 20 days |
| 1964 | 23 days |
| 1965 | 25 days |
| 1966 | 20 days |
| 1967 | 27 days |
| 1968 | 23 days |
| 1969 | 35 days |
| 1970 | 17 days |
| 1971 | 17 days |
| 1972 | 20 days |
| 1973 | 31 days |
| 1974 | 26 days |
| 1975 | 19 days |
| 1976 | 33 days |
| 1977 | 35 days |
| 1978 | 41 days |
| 1979 | 58 days |
| 1980 | 23 days |
| 1981 | 34 days |
| 1982 | 19 days |
| 1983 | 27 days |
| 1984 | 27 days |
| 1985 | 18 days |
| 1986 | 40 days |
| 1987 | 35 days |
| 1988 | 38 days |
| 1989 | 19 days |
| 1990 | 33 days |
| 1991 | 22 days |
| 1992 | 26 days |
| 1993 | 33 days |
| 1994 | 15 days |
| 1995 | 17 days |
| 1996 | 22 days |
| 1997 | 20 days |
| 1998 | 31 days |
| 1999 | 53 days |
| 2000 | 20 days |
| 2001 | 31 days |
| 2002 | 28 days |
| 2003 | 32 days |
| 2004 | 22 days |
| 2005 | 27 days |
| 2006 | 32 days |
| 2007 | 19 days |
| 2008 | 20 days |
| 2009 | 28 days |
| 2010 | 35 days |
| 2011 | 19 days |
| 2012 | 32 days |
| 2013 | 24 days |
| 2014 | 17 days |
| 2015 | 28 days |
| 2016 | 27 days |
| 2017 | 22 days |
| 2018 | 32 days |
| 2019 | 15 days |
| 2020 | 28 days |
| 2021 | 32 days |
| 2022 | 24 days |
| 2023 | 23 days |
| 2024 | 27 days |
| 2025 | 17 days |
| 2026 | 31 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
73 years with a frostAcross 73 years with a frost, the median last spring frost at Yellowstone Park Mammoth falls on 11 June and the median first autumn frost on 9 September, which leaves a median of 91 days between them.
In 1993 to 2024 the median growing season was 102 days. That is 30 days more than in 1896 to 1970.
Fitted over all years, the growing season changes by +4.6 days per decade at this station.
| Measure | Median, all years | Earliest period (1896 to 1970) | Recent period (1993 to 2024) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 11 June | 20 June | 10 June | 10 days earlier | -1.4 days per decade |
| First autumn frost | 9 September | 31 August | 17 September | 17 days later | +3.1 days per decade |
| Growing days | 91 days | 72 days | 102 days | 30 days more | +4.6 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
80 years, 1895 to 2024A day with at least 21.6 mm (0.9 in) of rain is expected about once in 2 years. A day with at least 57.6 mm (2.3 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 21.6 mm (0.9 in) | |
| 5 years | 28.3 mm (1.1 in) | |
| 10 years | 33.7 mm (1.3 in) | |
| 25 years | 41.9 mm (1.6 in) | |
| 50 years | 49.2 mm (1.9 in) | |
| 100 years | 57.6 mm (2.3 in) | Longer than the 80 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, 80 years of values from 1895 to 2024.
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: 57.9 mm (2.3 in) in 2022; 47.2 mm (1.9 in) in 1988; 46.7 mm (1.8 in) in 2010.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Climate Twins
2010 to 2024 against 1961 to 1990Over 2010 to 2024, Yellowstone Park Mammoth had a mean temperature of 5.3 C (41.5 F) and 386.0 mm (15.2 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Glenrock 14 SSE (United States, 468 km away), Evanston 1 E (United States, 413 km away) and Montpelier Rs (United States, 300 km away).
| Twin station | Country | Distance away | Mean temperature, 1961-1990 | Rain a year, 1961-1990 | Climate difference |
|---|---|---|---|---|---|
| Glenrock 14 SSE | United States | 468 km (291 mi) | 5.7 C (42.2 F) | 423.8 mm (16.7 in) | 0.86 |
| Evanston 1 E | United States | 413 km (257 mi) | 4.9 C (40.9 F) | 276.5 mm (10.9 in) | 0.93 |
| Montpelier Rs | United States | 300 km (186 mi) | 4.9 C (40.9 F) | 378.2 mm (14.9 in) | 0.94 |
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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-15).