Casper Mtn. Weather Records (USS0006G01S)
Record envelope, standing records and threshold days for Casper Mtn. (USS0006G01S), Wyoming, United States, with 48 years of record.
Key Facts for Casper Mtn.
- Casper Mtn. (USS0006G01S) is a weather station in Wyoming, United States at 42.73 latitude and -106.32 longitude, 2,408 m (7,900 ft) above sea level.
- The station reports from 1979 to 2026, 48 years of record.
- 1,464 records set at Casper Mtn. still stand.
- Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
- Casper Mtn. set a daily record high minimum temperature of 8.5 C (47.3 F) on 9 October 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, 42.73 latitude, -106.32 longitude.
- Elevation: 2,408 m (7,900 ft).
- Period of record: 1979 to 2026, 48 years.
- Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
20 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 19.1 C (66.4 F) | -32.2 C (-26.0 F) | 5.1 C (41.2 F) | -22.9 C (-9.2 F) |
| Feb | 13.6 C (56.5 F) | -34.8 C (-30.6 F) | 8.1 C (46.6 F) | -19.0 C (-2.2 F) |
| Mar | 28.8 C (83.8 F) | -28.3 C (-18.9 F) | 19.2 C (66.6 F) | -16.4 C (2.5 F) |
| Apr | 32.9 C (91.2 F) | -20.8 C (-5.4 F) | 19.0 C (66.2 F) | -10.4 C (13.3 F) |
| May | 31.5 C (88.7 F) | -13.9 C (7.0 F) | 24.6 C (76.3 F) | -10.2 C (13.6 F) |
| Jun | 36.3 C (97.3 F) | -5.4 C (22.3 F) | 27.0 C (80.6 F) | -1.0 C (30.2 F) |
| Jul | 39.8 C (103.6 F) | 0.3 C (32.5 F) | 30.8 C (87.4 F) | 7.0 C (44.6 F) |
| Aug | 46.2 C (115.2 F) | -6.2 C (20.8 F) | 31.2 C (88.2 F) | 4.3 C (39.7 F) |
| Sep | 47.8 C (118.0 F) | -17.1 C (1.2 F) | 25.4 C (77.7 F) | 1.7 C (35.1 F) |
| Oct | 31.7 C (89.1 F) | -24.5 C (-12.1 F) | 22.0 C (71.6 F) | 3.0 C (37.4 F) |
| Nov | 37.4 C (99.3 F) | -26.9 C (-16.4 F) | n/a | n/a |
| Dec | 28.8 C (83.8 F) | -37.8 C (-36.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1981 | 5 |
| 1982 | 51 |
| 1983 | 7 |
| 1984 | 38 |
| 1985 | 31 |
| 1986 | 8 |
| 1987 | 33 |
| 1988 | 28 |
| 1989 | 31 |
| 1990 | 35 |
| 1991 | 23 |
| 1992 | 26 |
| 1993 | 36 |
| 1994 | 17 |
| 1995 | 37 |
| 1996 | 42 |
| 1997 | 26 |
| 1998 | 20 |
| 1999 | 29 |
| 2000 | 41 |
| 2001 | 13 |
| 2002 | 31 |
| 2003 | 43 |
| 2004 | 56 |
| 2005 | 75 |
| 2006 | 43 |
| 2007 | 26 |
| 2008 | 26 |
| 2009 | 33 |
| 2010 | 23 |
| 2011 | 21 |
| 2012 | 33 |
| 2013 | 44 |
| 2014 | 20 |
| 2015 | 50 |
| 2016 | 36 |
| 2017 | 23 |
| 2018 | 24 |
| 2019 | 27 |
| 2020 | 38 |
| 2021 | 40 |
| 2022 | 35 |
| 2023 | 24 |
| 2024 | 30 |
| 2025 | 39 |
| 2026 | 47 |
All-Time Record Progression
1 new records| Date | Kind | Detail |
|---|---|---|
| 2026-07-25 | Record high minimum temperature | Record high minimum temperature 19.1 C (66.4 F) |
Wettest Day of Each Month
May: 127.0 mm (5.0 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 27.9 mm (1.1 in) | 8 January 2006 |
| Feb | 58.4 mm (2.3 in) | 14 February 1987 |
| Mar | 53.3 mm (2.1 in) | 23 March 2009 |
| Apr | 94.0 mm (3.7 in) | 6 April 1993 |
| May | 127.0 mm (5.0 in) | 8 May 1995 |
| Jun | 109.2 mm (4.3 in) | 3 June 1986 |
| Jul | 48.3 mm (1.9 in) | 30 July 2021 |
| Aug | 33.0 mm (1.3 in) | 13 August 2022 |
| Sep | 53.3 mm (2.1 in) | 7 September 2001 |
| Oct | 86.4 mm (3.4 in) | 12 October 2023 |
| Nov | 48.3 mm (1.9 in) | 25 November 1983 |
| Dec | 27.9 mm (1.1 in) | 21 December 2011 |
Period of Record Coverage
1981 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1981 | 38 | 10% | No |
| 1982 | 213 | 58% | No |
| 1983 | 62 | 17% | No |
| 1984 | 220 | 60% | No |
| 1985 | 273 | 75% | No |
| 1986 | 251 | 69% | No |
| 1987 | 358 | 98% | Yes |
| 1988 | 350 | 96% | Yes |
| 1989 | 320 | 88% | No |
| 1990 | 345 | 95% | Yes |
| 1991 | 361 | 99% | Yes |
| 1992 | 364 | 99% | Yes |
| 1993 | 329 | 90% | Yes |
| 1994 | 324 | 89% | No |
| 1995 | 363 | 99% | Yes |
| 1996 | 355 | 97% | Yes |
| 1997 | 364 | 100% | Yes |
| 1998 | 361 | 99% | Yes |
| 1999 | 364 | 100% | Yes |
| 2000 | 366 | 100% | Yes |
| 2001 | 363 | 99% | Yes |
| 2002 | 364 | 100% | Yes |
| 2003 | 365 | 100% | Yes |
| 2004 | 292 | 80% | No |
| 2005 | 196 | 54% | No |
| 2006 | 334 | 92% | Yes |
| 2007 | 365 | 100% | Yes |
| 2008 | 366 | 100% | Yes |
| 2009 | 339 | 93% | Yes |
| 2010 | 360 | 99% | Yes |
| 2011 | 364 | 100% | Yes |
| 2012 | 366 | 100% | Yes |
| 2013 | 365 | 100% | Yes |
| 2014 | 260 | 71% | No |
| 2015 | 235 | 64% | No |
| 2016 | 341 | 93% | 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 | 356 | 98% | Yes |
| 2024 | 364 | 99% | Yes |
| 2025 | 364 | 100% | Yes |
| 2026 | 282 | 77% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 9 October 2026 | Casper Mtn., US | daily high min (Provisional) | 8.5 C (47.3 F) | 0.3 C (0.5 F) | 5 years | 5 of 100 (Routine) |
| 8 October 2026 | Casper Mtn., US | daily high min (Provisional) | 8.6 C (47.5 F) | 0.5 C (0.9 F) | 5 years | 5 of 100 (Routine) |
| 7 October 2026 | Casper Mtn., US | daily high min (Provisional) | 8.7 C (47.7 F) | 2.1 C (3.8 F) | 23 years | 13 of 100 (Routine) |
| 7 October 2026 | Casper Mtn., US | daily high max (Tie, Provisional) | 19.7 C (67.5 F) | tie | 28 years | 3 of 100 (Routine) |
| 6 October 2026 | Casper Mtn., US | daily high min (Provisional) | 11.0 C (51.8 F) | 3.5 C (6.3 F) | 11 years | 13 of 100 (Routine) |
| 5 October 2026 | Casper Mtn., US | daily high min (Provisional) | 10.4 C (50.7 F) | 1.2 C (2.2 F) | 19 years | 11 of 100 (Routine) |
| 5 October 2026 | Casper Mtn., US | daily high max (Provisional) | 22.0 C (71.6 F) | 0.5 C (0.9 F) | 20 years | 10 of 100 (Routine) |
| 13 September 2026 | Casper Mtn., US | daily high max (Provisional) | 24.3 C (75.7 F) | 0.9 C (1.6 F) | 28 years | 13 of 100 (Routine) |
| 21 August 2026 | Casper Mtn., US | daily high min (Provisional) | 16.1 C (61.0 F) | 0.9 C (1.6 F) | 0 years | 6 of 100 (Routine) |
| 16 August 2026 | Casper Mtn., US | daily rain (Provisional) | 5.1 mm (0.20 in) | 2.6 mm (0.10 in) | 16 years | 13 of 100 (Routine) |
| 11 August 2026 | Casper Mtn., US | daily high min | 17.2 C (63.0 F) | 1.7 C (3.1 F) | 23 years | 15 of 100 (Routine) |
| 9 August 2026 | Casper Mtn., US | daily high min | 16.6 C (61.9 F) | 0.2 C (0.4 F) | 13 years | 8 of 100 (Routine) |
| 2 August 2026 | Casper Mtn., US | monthly high min | 18.8 C (65.8 F) | 0.8 C (1.4 F) | 5 years | 17 of 100 (Routine) |
| 26 July 2026 | Casper Mtn., US | daily high max | 30.0 C (86.0 F) | 0.8 C (1.4 F) | 39 years | 16 of 100 (Routine) |
| 25 July 2026 | Casper Mtn., US | all-time high min | 19.1 C (66.4 F) | 0.6 C (1.1 F) | 19 years | 30 of 100 (Routine) |
| 22 July 2026 | Casper Mtn., US | daily rain (Tie) | 7.6 mm (0.30 in) | tie | 17 years | 2 of 100 (Routine) |
| 21 July 2026 | Casper Mtn., US | daily high min | 16.4 C (61.5 F) | 1.0 C (1.8 F) | 13 years | 11 of 100 (Routine) |
| 20 July 2026 | Casper Mtn., US | daily high min | 17.6 C (63.7 F) | 0.5 C (0.9 F) | 13 years | 9 of 100 (Routine) |
| 13 July 2026 | Casper Mtn., US | daily high min | 17.2 C (63.0 F) | 1.2 C (2.2 F) | 13 years | 11 of 100 (Routine) |
| 12 July 2026 | Casper Mtn., US | daily high min | 15.8 C (60.4 F) | 1.5 C (2.7 F) | 5 years | 9 of 100 (Routine) |
Climate Trend
29 complete years, 1987 to 2025| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1987 | 4.3 C | +0.80 C |
| 1991 | 2.9 C | -0.62 C |
| 1992 | 3.1 C | -0.39 C |
| 1993 | 1.2 C | -2.32 C |
| 1995 | 2.8 C | -0.71 C |
| 1996 | 3.3 C | -0.19 C |
| 1997 | 2.7 C | -0.81 C |
| 1998 | 3.8 C | +0.26 C |
| 1999 | 3.9 C | +0.39 C |
| 2000 | 3.6 C | +0.05 C |
| 2001 | 4.2 C | +0.68 C |
| 2002 | 2.8 C | -0.76 C |
| 2003 | 3.9 C | +0.35 C |
| 2006 | 3.6 C | +0.10 C |
| 2007 | 4.0 C | +0.50 C |
| 2008 | 2.5 C | -1.00 C |
| 2010 | 3.5 C | +0.03 C |
| 2011 | 3.1 C | -0.44 C |
| 2012 | 5.1 C | +1.63 C |
| 2013 | 3.2 C | -0.27 C |
| 2017 | 4.1 C | +0.60 C |
| 2018 | 3.7 C | +0.19 C |
| 2019 | 2.6 C | -0.87 C |
| 2020 | 3.9 C | +0.34 C |
| 2021 | 4.1 C | +0.57 C |
| 2022 | 3.3 C | -0.24 C |
| 2023 | 3.3 C | -0.24 C |
| 2024 | 4.7 C | +1.21 C |
| 2025 | 4.6 C | +1.08 C |
This station does not have enough complete years (30 are needed) to fit a temperature trend.
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
1979 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 47.8 C (118.0 F) | 2004 | 29.8 C (85.6 F) | 46 |
| Coldest night (TNn) | -37.8 C (-36.0 F) | 1990 | -27.6 C (-17.7 F) | 45 |
| Wettest day (Rx1day) | 127.0 mm (5.0 in) | 1995 | 40.6 mm (1.6 in) | 46 |
| Wettest five days (Rx5day) | 213.4 mm (8.4 in) | 1995 | 71.1 mm (2.8 in) | 45 |
| Longest dry spell (CDD) | 51 days | 2011 | 26 days | 46 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1979 | n/a |
| 1981 | 6.8 C (44.2 F) |
| 1982 | 18.0 C (64.4 F) |
| 1983 | 5.8 C (42.4 F) |
| 1984 | 17.1 C (62.8 F) |
| 1985 | 21.0 C (69.8 F) |
| 1986 | 20.9 C (69.6 F) |
| 1987 | 29.7 C (85.5 F) |
| 1988 | 31.3 C (88.3 F) |
| 1989 | 32.0 C (89.6 F) |
| 1990 | 31.5 C (88.7 F) |
| 1991 | 29.3 C (84.7 F) |
| 1992 | 27.3 C (81.1 F) |
| 1993 | 29.0 C (84.2 F) |
| 1994 | 28.9 C (84.0 F) |
| 1995 | 32.0 C (89.6 F) |
| 1996 | 29.4 C (84.9 F) |
| 1997 | 29.8 C (85.6 F) |
| 1998 | 30.5 C (86.9 F) |
| 1999 | 29.5 C (85.1 F) |
| 2000 | 30.4 C (86.7 F) |
| 2001 | 31.4 C (88.5 F) |
| 2002 | 31.5 C (88.7 F) |
| 2003 | 32.1 C (89.8 F) |
| 2004 | 47.8 C (118.0 F) |
| 2005 | 39.8 C (103.6 F) |
| 2006 | 36.3 C (97.3 F) |
| 2007 | 29.5 C (85.1 F) |
| 2008 | 29.5 C (85.1 F) |
| 2009 | 28.5 C (83.3 F) |
| 2010 | 28.6 C (83.5 F) |
| 2011 | 28.4 C (83.1 F) |
| 2012 | 30.0 C (86.0 F) |
| 2013 | 30.0 C (86.0 F) |
| 2014 | 30.2 C (86.4 F) |
| 2015 | 31.1 C (88.0 F) |
| 2016 | 32.1 C (89.8 F) |
| 2017 | 28.2 C (82.8 F) |
| 2018 | 30.8 C (87.4 F) |
| 2019 | 28.0 C (82.4 F) |
| 2020 | 29.1 C (84.4 F) |
| 2021 | 31.2 C (88.2 F) |
| 2022 | 29.5 C (85.1 F) |
| 2023 | 30.2 C (86.4 F) |
| 2024 | 30.4 C (86.7 F) |
| 2025 | 29.5 C (85.1 F) |
| 2026 | 31.2 C (88.2 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1979 | n/a |
| 1981 | n/a |
| 1982 | -19.9 C (-3.8 F) |
| 1983 | -34.9 C (-30.8 F) |
| 1984 | -28.4 C (-19.1 F) |
| 1985 | -17.1 C (1.2 F) |
| 1986 | -24.2 C (-11.6 F) |
| 1987 | -22.8 C (-9.0 F) |
| 1988 | -22.1 C (-7.8 F) |
| 1989 | -34.8 C (-30.6 F) |
| 1990 | -37.8 C (-36.0 F) |
| 1991 | -28.0 C (-18.4 F) |
| 1992 | -27.1 C (-16.8 F) |
| 1993 | -29.4 C (-20.9 F) |
| 1994 | -20.5 C (-4.9 F) |
| 1995 | -27.7 C (-17.9 F) |
| 1996 | -28.7 C (-19.7 F) |
| 1997 | -30.7 C (-23.3 F) |
| 1998 | -30.9 C (-23.6 F) |
| 1999 | -19.9 C (-3.8 F) |
| 2000 | -22.8 C (-9.0 F) |
| 2001 | -25.6 C (-14.1 F) |
| 2002 | -25.3 C (-13.5 F) |
| 2003 | -21.3 C (-6.3 F) |
| 2004 | -29.1 C (-20.4 F) |
| 2005 | -29.3 C (-20.7 F) |
| 2006 | -27.3 C (-17.1 F) |
| 2007 | -28.5 C (-19.3 F) |
| 2008 | -30.8 C (-23.4 F) |
| 2009 | -25.0 C (-13.0 F) |
| 2010 | -26.7 C (-16.1 F) |
| 2011 | -32.2 C (-26.0 F) |
| 2012 | -20.0 C (-4.0 F) |
| 2013 | -27.6 C (-17.7 F) |
| 2014 | -31.2 C (-24.2 F) |
| 2015 | -24.8 C (-12.6 F) |
| 2016 | -31.6 C (-24.9 F) |
| 2017 | -27.3 C (-17.1 F) |
| 2018 | -28.7 C (-19.7 F) |
| 2019 | -26.6 C (-15.9 F) |
| 2020 | -22.5 C (-8.5 F) |
| 2021 | -27.7 C (-17.9 F) |
| 2022 | -33.5 C (-28.3 F) |
| 2023 | -27.3 C (-17.1 F) |
| 2024 | -32.2 C (-26.0 F) |
| 2025 | -27.9 C (-18.2 F) |
| 2026 | -22.9 C (-9.2 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1979 | 20.3 mm (0.8 in) |
| 1981 | n/a |
| 1982 | 33.0 mm (1.3 in) |
| 1983 | 48.3 mm (1.9 in) |
| 1984 | 40.6 mm (1.6 in) |
| 1985 | 40.6 mm (1.6 in) |
| 1986 | 109.2 mm (4.3 in) |
| 1987 | 58.4 mm (2.3 in) |
| 1988 | 25.4 mm (1.0 in) |
| 1989 | 35.6 mm (1.4 in) |
| 1990 | 45.7 mm (1.8 in) |
| 1991 | 53.3 mm (2.1 in) |
| 1992 | 33.0 mm (1.3 in) |
| 1993 | 94.0 mm (3.7 in) |
| 1994 | 27.9 mm (1.1 in) |
| 1995 | 127.0 mm (5.0 in) |
| 1996 | 63.5 mm (2.5 in) |
| 1997 | 50.8 mm (2.0 in) |
| 1998 | 61.0 mm (2.4 in) |
| 1999 | 30.5 mm (1.2 in) |
| 2000 | 48.3 mm (1.9 in) |
| 2001 | 53.3 mm (2.1 in) |
| 2002 | 27.9 mm (1.1 in) |
| 2003 | 35.6 mm (1.4 in) |
| 2004 | 20.3 mm (0.8 in) |
| 2005 | 22.9 mm (0.9 in) |
| 2006 | 30.5 mm (1.2 in) |
| 2007 | 61.0 mm (2.4 in) |
| 2008 | 86.4 mm (3.4 in) |
| 2009 | 53.3 mm (2.1 in) |
| 2010 | 43.2 mm (1.7 in) |
| 2011 | 53.3 mm (2.1 in) |
| 2012 | 30.5 mm (1.2 in) |
| 2013 | 83.8 mm (3.3 in) |
| 2014 | 27.9 mm (1.1 in) |
| 2015 | 38.1 mm (1.5 in) |
| 2016 | 40.6 mm (1.6 in) |
| 2017 | 40.6 mm (1.6 in) |
| 2018 | 25.4 mm (1.0 in) |
| 2019 | 53.3 mm (2.1 in) |
| 2020 | 20.3 mm (0.8 in) |
| 2021 | 48.3 mm (1.9 in) |
| 2022 | 35.6 mm (1.4 in) |
| 2023 | 86.4 mm (3.4 in) |
| 2024 | 55.9 mm (2.2 in) |
| 2025 | 33.0 mm (1.3 in) |
| 2026 | 35.6 mm (1.4 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1979 | n/a |
| 1981 | n/a |
| 1982 | 76.2 mm (3.0 in) |
| 1983 | 94.1 mm (3.7 in) |
| 1984 | 81.3 mm (3.2 in) |
| 1985 | 55.8 mm (2.2 in) |
| 1986 | 114.3 mm (4.5 in) |
| 1987 | 60.9 mm (2.4 in) |
| 1988 | 53.4 mm (2.1 in) |
| 1989 | 71.1 mm (2.8 in) |
| 1990 | 61.0 mm (2.4 in) |
| 1991 | 83.8 mm (3.3 in) |
| 1992 | 50.8 mm (2.0 in) |
| 1993 | 114.2 mm (4.5 in) |
| 1994 | 40.6 mm (1.6 in) |
| 1995 | 213.4 mm (8.4 in) |
| 1996 | 96.6 mm (3.8 in) |
| 1997 | 78.7 mm (3.1 in) |
| 1998 | 73.6 mm (2.9 in) |
| 1999 | 58.4 mm (2.3 in) |
| 2000 | 66.0 mm (2.6 in) |
| 2001 | 60.9 mm (2.4 in) |
| 2002 | 48.2 mm (1.9 in) |
| 2003 | 66.0 mm (2.6 in) |
| 2004 | 43.1 mm (1.7 in) |
| 2005 | 43.2 mm (1.7 in) |
| 2006 | 71.2 mm (2.8 in) |
| 2007 | 73.7 mm (2.9 in) |
| 2008 | 96.5 mm (3.8 in) |
| 2009 | 60.9 mm (2.4 in) |
| 2010 | 66.1 mm (2.6 in) |
| 2011 | 96.5 mm (3.8 in) |
| 2012 | 53.3 mm (2.1 in) |
| 2013 | 111.7 mm (4.4 in) |
| 2014 | 45.6 mm (1.8 in) |
| 2015 | 76.2 mm (3.0 in) |
| 2016 | 71.1 mm (2.8 in) |
| 2017 | 83.7 mm (3.3 in) |
| 2018 | 40.6 mm (1.6 in) |
| 2019 | 78.8 mm (3.1 in) |
| 2020 | 50.8 mm (2.0 in) |
| 2021 | 68.5 mm (2.7 in) |
| 2022 | 88.9 mm (3.5 in) |
| 2023 | 127.1 mm (5.0 in) |
| 2024 | 116.9 mm (4.6 in) |
| 2025 | 45.7 mm (1.8 in) |
| 2026 | 61.0 mm (2.4 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1979 | 1 day |
| 1981 | n/a |
| 1982 | 11 days |
| 1983 | 24 days |
| 1984 | 30 days |
| 1985 | 22 days |
| 1986 | 23 days |
| 1987 | 31 days |
| 1988 | 20 days |
| 1989 | 29 days |
| 1990 | 26 days |
| 1991 | 22 days |
| 1992 | 21 days |
| 1993 | 23 days |
| 1994 | 14 days |
| 1995 | 43 days |
| 1996 | 23 days |
| 1997 | 26 days |
| 1998 | 26 days |
| 1999 | 27 days |
| 2000 | 19 days |
| 2001 | 26 days |
| 2002 | 25 days |
| 2003 | 20 days |
| 2004 | 35 days |
| 2005 | 32 days |
| 2006 | 46 days |
| 2007 | 25 days |
| 2008 | 34 days |
| 2009 | 27 days |
| 2010 | 45 days |
| 2011 | 51 days |
| 2012 | 38 days |
| 2013 | 21 days |
| 2014 | 17 days |
| 2015 | 26 days |
| 2016 | 22 days |
| 2017 | 29 days |
| 2018 | 42 days |
| 2019 | 34 days |
| 2020 | 36 days |
| 2021 | 35 days |
| 2022 | 29 days |
| 2023 | 20 days |
| 2024 | 27 days |
| 2025 | 18 days |
| 2026 | 33 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
29 years with a frostAcross 29 years with a frost, the median last spring frost at Casper Mtn. falls on 9 June and the median first autumn frost on 19 September, which leaves a median of 105 days between them.
Fitted over all years, the growing season changes by +8.9 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1987 to 2025) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 9 June | n/a | 9 June | n/a | -3.0 days per decade |
| First autumn frost | 19 September | n/a | 19 September | n/a | +5.9 days per decade |
| Growing days | 105 days | n/a | 105 days | n/a | +8.9 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
43 years, 1983 to 2025A day with at least 42.9 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 141.1 mm (5.6 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 42.9 mm (1.7 in) | |
| 5 years | 63.0 mm (2.5 in) | |
| 10 years | 78.4 mm (3.1 in) | |
| 25 years | 100.9 mm (4.0 in) | |
| 50 years | 119.9 mm (4.7 in) | Longer than the 43 years of record |
| 100 years | 141.1 mm (5.6 in) | Longer than the 43 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, 43 years of values from 1983 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: 127.0 mm (5.0 in) in 1995; 109.2 mm (4.3 in) in 1986; 94.0 mm (3.7 in) in 1993.
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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 2026-10-12 (12 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-13).