Boysen Dam Weather Records (USC00481000)
Record envelope, standing records and threshold days for Boysen Dam (USC00481000), Wyoming, United States, with 79 years of record.
Key Facts for Boysen Dam
- Boysen Dam (USC00481000) is a weather station in Wyoming, United States at 43.41 latitude and -108.16 longitude, 1,486 m (4,875 ft) above sea level.
- The station reports from 1948 to 2026, 79 years of record.
- 1,464 records set at Boysen Dam still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Boysen Dam tied a daily record high maximum temperature of 28.3 C (82.9 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, 43.41 latitude, -108.16 longitude.
- Elevation: 1,486 m (4,875 ft).
- Period of record: 1948 to 2026, 79 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
34 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 21.1 C (70.0 F) | -39.4 C (-38.9 F) | 14.4 C (57.9 F) | -21.7 C (-7.1 F) |
| Feb | 20.6 C (69.1 F) | -37.8 C (-36.0 F) | 17.2 C (63.0 F) | -19.4 C (-2.9 F) |
| Mar | 28.3 C (82.9 F) | -29.4 C (-20.9 F) | 28.3 C (82.9 F) | -10.0 C (14.0 F) |
| Apr | 31.1 C (88.0 F) | -16.7 C (1.9 F) | 28.9 C (84.0 F) | -5.0 C (23.0 F) |
| May | 36.1 C (97.0 F) | -6.7 C (19.9 F) | 33.3 C (91.9 F) | -2.8 C (27.0 F) |
| Jun | 39.4 C (102.9 F) | -2.8 C (27.0 F) | 35.6 C (96.1 F) | 5.6 C (42.1 F) |
| Jul | 42.2 C (108.0 F) | 5.0 C (41.0 F) | 41.7 C (107.1 F) | 10.6 C (51.1 F) |
| Aug | 40.6 C (105.1 F) | 3.3 C (37.9 F) | 40.6 C (105.1 F) | 8.3 C (46.9 F) |
| Sep | 38.9 C (102.0 F) | -8.9 C (16.0 F) | 33.9 C (93.0 F) | 6.1 C (43.0 F) |
| Oct | 31.7 C (89.1 F) | -19.4 C (-2.9 F) | 30.6 C (87.1 F) | 2.8 C (37.0 F) |
| Nov | 21.7 C (71.1 F) | -26.1 C (-15.0 F) | n/a | n/a |
| Dec | 18.3 C (64.9 F) | -37.8 C (-36.0 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1948 | 10 |
| 1949 | 40 |
| 1950 | 40 |
| 1951 | 19 |
| 1952 | 18 |
| 1953 | 20 |
| 1954 | 38 |
| 1955 | 28 |
| 1956 | 16 |
| 1957 | 8 |
| 1958 | 17 |
| 1959 | 18 |
| 1960 | 17 |
| 1961 | 9 |
| 1962 | 25 |
| 1963 | 32 |
| 1964 | 16 |
| 1965 | 25 |
| 1966 | 13 |
| 1967 | 16 |
| 1968 | 9 |
| 1969 | 19 |
| 1970 | 19 |
| 1971 | 13 |
| 1972 | 38 |
| 1973 | 16 |
| 1974 | 8 |
| 1975 | 19 |
| 1976 | 7 |
| 1977 | 13 |
| 1978 | 24 |
| 1979 | 24 |
| 1980 | 14 |
| 1981 | 11 |
| 1982 | 30 |
| 1983 | 23 |
| 1984 | 10 |
| 1985 | 35 |
| 1986 | 15 |
| 1987 | 16 |
| 1988 | 23 |
| 1989 | 27 |
| 1990 | 21 |
| 1991 | 18 |
| 1992 | 15 |
| 1993 | 27 |
| 1994 | 7 |
| 1995 | 10 |
| 1996 | 17 |
| 1997 | 6 |
| 1998 | 11 |
| 1999 | 13 |
| 2000 | 14 |
| 2001 | 6 |
| 2002 | 16 |
| 2003 | 19 |
| 2004 | 14 |
| 2005 | 7 |
| 2006 | 30 |
| 2007 | 20 |
| 2008 | 13 |
| 2009 | 26 |
| 2010 | 8 |
| 2011 | 12 |
| 2012 | 19 |
| 2013 | 16 |
| 2014 | 23 |
| 2015 | 17 |
| 2016 | 10 |
| 2017 | 7 |
| 2018 | 11 |
| 2019 | 19 |
| 2020 | 25 |
| 2021 | 25 |
| 2022 | 17 |
| 2023 | 25 |
| 2024 | 14 |
| 2025 | 21 |
| 2026 | 47 |
All-Time Record Progression
3 new records| Date | Kind | Detail |
|---|---|---|
| 1979-01-31 | Record low minimum temperature | Record low minimum temperature -39.4 C (-38.9 F) |
| 1991-04-13 | Record daily snowfall | Record daily snowfall 25.4 cm (10.0 in) |
| 2007-03-30 | Record daily snowfall | Record daily snowfall 30.5 cm (12.0 in) |
Wettest Day of Each Month
Jun: 63.8 mm (2.5 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 12.7 mm (0.5 in) | 23 January 1964 |
| Feb | 15.2 mm (0.6 in) | 22 February 2019 |
| Mar | 26.7 mm (1.1 in) | 23 March 1973 |
| Apr | 57.2 mm (2.3 in) | 23 April 1957 |
| May | 50.8 mm (2.0 in) | 18 May 1978 |
| Jun | 63.8 mm (2.5 in) | 22 June 1964 |
| Jul | 49.5 mm (1.9 in) | 26 July 2007 |
| Aug | 29.0 mm (1.1 in) | 31 August 1963 |
| Sep | 42.2 mm (1.7 in) | 12 September 2019 |
| Oct | 47.0 mm (1.9 in) | 4 October 2016 |
| Nov | 14.0 mm (0.6 in) | 25 November 1968 |
| Dec | 31.8 mm (1.3 in) | 2 December 1982 |
Period of Record Coverage
1948 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1948 | 152 | 42% | No |
| 1949 | 357 | 98% | Yes |
| 1950 | 365 | 100% | Yes |
| 1951 | 364 | 100% | Yes |
| 1952 | 345 | 94% | Yes |
| 1953 | 344 | 94% | Yes |
| 1954 | 334 | 92% | Yes |
| 1955 | 340 | 93% | Yes |
| 1956 | 363 | 99% | Yes |
| 1957 | 334 | 92% | Yes |
| 1958 | 363 | 99% | Yes |
| 1959 | 362 | 99% | Yes |
| 1960 | 365 | 100% | Yes |
| 1961 | 362 | 99% | Yes |
| 1962 | 364 | 100% | Yes |
| 1963 | 365 | 100% | Yes |
| 1964 | 360 | 98% | Yes |
| 1965 | 362 | 99% | Yes |
| 1966 | 361 | 99% | Yes |
| 1967 | 363 | 99% | Yes |
| 1968 | 359 | 98% | Yes |
| 1969 | 362 | 99% | Yes |
| 1970 | 362 | 99% | Yes |
| 1971 | 364 | 100% | Yes |
| 1972 | 365 | 100% | Yes |
| 1973 | 364 | 100% | Yes |
| 1974 | 364 | 100% | Yes |
| 1975 | 309 | 85% | No |
| 1976 | 319 | 87% | No |
| 1977 | 362 | 99% | Yes |
| 1978 | 357 | 98% | Yes |
| 1979 | 358 | 98% | Yes |
| 1980 | 363 | 99% | Yes |
| 1981 | 362 | 99% | Yes |
| 1982 | 308 | 84% | No |
| 1983 | 348 | 95% | Yes |
| 1984 | 326 | 89% | No |
| 1985 | 303 | 83% | No |
| 1986 | 287 | 79% | No |
| 1987 | 312 | 85% | No |
| 1988 | 335 | 92% | Yes |
| 1989 | 342 | 94% | Yes |
| 1990 | 355 | 97% | Yes |
| 1991 | 361 | 99% | Yes |
| 1992 | 365 | 100% | Yes |
| 1993 | 363 | 99% | Yes |
| 1994 | 298 | 82% | No |
| 1995 | 227 | 62% | No |
| 1996 | 229 | 63% | No |
| 1997 | 295 | 81% | No |
| 1998 | 361 | 99% | Yes |
| 1999 | 364 | 100% | Yes |
| 2000 | 365 | 100% | Yes |
| 2001 | 359 | 98% | Yes |
| 2002 | 365 | 100% | Yes |
| 2003 | 333 | 91% | Yes |
| 2004 | 335 | 92% | Yes |
| 2005 | 332 | 91% | Yes |
| 2006 | 339 | 93% | Yes |
| 2007 | 357 | 98% | Yes |
| 2008 | 364 | 99% | Yes |
| 2009 | 363 | 99% | Yes |
| 2010 | 364 | 100% | Yes |
| 2011 | 363 | 99% | Yes |
| 2012 | 365 | 100% | Yes |
| 2013 | 360 | 99% | Yes |
| 2014 | 363 | 99% | Yes |
| 2015 | 364 | 100% | Yes |
| 2016 | 364 | 99% | 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 | 364 | 100% | Yes |
| 2024 | 366 | 100% | Yes |
| 2025 | 365 | 100% | Yes |
| 2026 | 283 | 78% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 9 October 2026 | Boysen Dam, US | daily high max (Tie, Provisional) | 28.3 C (82.9 F) | tie | 73 years | 7 of 100 (Routine) |
| 7 October 2026 | Boysen Dam, US | daily high max (Provisional) | 30.6 C (87.1 F) | 1.2 C (2.2 F) | 51 years | 23 of 100 (Routine) |
| 6 October 2026 | Boysen Dam, US | daily high max (Tie, Provisional) | 28.3 C (82.9 F) | tie | 51 years | 5 of 100 (Routine) |
| 20 September 2026 | Boysen Dam, US | daily rain (Provisional) | 41.7 mm (1.6 in) | 25.4 mm (1.0 in) | 77 years | 70 of 100 (Major) |
| 22 August 2026 | Boysen Dam, US | daily high max (Provisional) | 37.2 C (99.0 F) | 0.5 C (0.9 F) | 65 years | 27 of 100 (Routine) |
| 4 August 2026 | Boysen Dam, US | monthly high max (Tie) | 40.6 C (105.1 F) | tie | 0 years | 4 of 100 (Routine) |
| 3 August 2026 | Boysen Dam, US | monthly high max | 40.6 C (105.1 F) | 0.6 C (1.1 F) | 46 years | 32 of 100 (Routine) |
| 2 August 2026 | Boysen Dam, US | daily high max | 38.9 C (102.0 F) | 0.6 C (1.1 F) | 17 years | 13 of 100 (Routine) |
| 27 July 2026 | Boysen Dam, US | daily high max | 39.4 C (102.9 F) | 1.1 C (2.0 F) | 4 years | 11 of 100 (Routine) |
| 27 July 2026 | Boysen Dam, US | daily high min (Tie) | 21.7 C (71.1 F) | tie | 65 years | 6 of 100 (Routine) |
| 26 July 2026 | Boysen Dam, US | daily high min | 21.1 C (70.0 F) | 1.1 C (2.0 F) | 60 years | 28 of 100 (Routine) |
| 26 July 2026 | Boysen Dam, US | daily high max (Tie) | 38.9 C (102.0 F) | tie | 67 years | 6 of 100 (Routine) |
| 21 July 2026 | Boysen Dam, US | daily high min (Tie) | 22.2 C (72.0 F) | tie | 71 years | 7 of 100 (Routine) |
| 15 July 2026 | Boysen Dam, US | daily high min | 22.8 C (73.0 F) | 2.8 C (5.0 F) | 72 years | 38 of 100 (Notable) |
| 15 July 2026 | Boysen Dam, US | daily high max | 40.6 C (105.1 F) | 0.6 C (1.1 F) | 37 years | 19 of 100 (Routine) |
| 14 July 2026 | Boysen Dam, US | daily high min | 21.1 C (70.0 F) | 0.5 C (0.9 F) | 56 years | 25 of 100 (Routine) |
| 14 July 2026 | Boysen Dam, US | daily high max | 40.0 C (104.0 F) | 0.6 C (1.1 F) | 24 years | 15 of 100 (Routine) |
| 13 July 2026 | Boysen Dam, US | daily high max | 41.7 C (107.1 F) | 2.8 C (5.0 F) | 72 years | 35 of 100 (Notable) |
| 13 July 2026 | Boysen Dam, US | daily high min | 23.3 C (73.9 F) | 0.5 C (0.9 F) | 72 years | 29 of 100 (Routine) |
| 7 June 2026 | Boysen Dam, US | daily high max | 35.0 C (95.0 F) | 1.7 C (3.1 F) | 37 years | 21 of 100 (Routine) |
Climate Trend
60 complete years, 1949 to 2025| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1949 | 7.4 C | -0.93 C |
| 1950 | 7.6 C | -0.76 C |
| 1951 | 7.2 C | -1.14 C |
| 1953 | 10.3 C | +1.93 C |
| 1956 | 8.5 C | +0.14 C |
| 1958 | 9.6 C | +1.21 C |
| 1959 | 8.5 C | +0.17 C |
| 1960 | 8.8 C | +0.46 C |
| 1961 | 8.4 C | +0.03 C |
| 1962 | 8.5 C | +0.11 C |
| 1963 | 9.7 C | +1.36 C |
| 1964 | 8.5 C | +0.10 C |
| 1965 | 8.7 C | +0.30 C |
| 1966 | 9.2 C | +0.82 C |
| 1967 | 8.9 C | +0.56 C |
| 1968 | 7.7 C | -0.69 C |
| 1969 | 9.6 C | +1.20 C |
| 1970 | 9.0 C | +0.59 C |
| 1971 | 8.8 C | +0.42 C |
| 1972 | 8.5 C | +0.10 C |
| 1973 | 7.0 C | -1.41 C |
| 1974 | 9.0 C | +0.67 C |
| 1977 | 9.1 C | +0.77 C |
| 1978 | 6.8 C | -1.61 C |
| 1979 | 7.2 C | -1.18 C |
| 1980 | 8.5 C | +0.13 C |
| 1981 | 9.7 C | +1.36 C |
| 1983 | 8.3 C | -0.09 C |
| 1987 | 9.3 C | +0.93 C |
| 1988 | 9.7 C | +1.38 C |
| 1989 | 8.5 C | +0.18 C |
| 1990 | 9.3 C | +0.98 C |
| 1991 | 7.9 C | -0.44 C |
| 1992 | 8.2 C | -0.17 C |
| 1993 | 5.3 C | -3.07 C |
| 1998 | 8.5 C | +0.17 C |
| 1999 | 9.1 C | +0.71 C |
| 2000 | 8.2 C | -0.12 C |
| 2001 | 8.2 C | -0.18 C |
| 2002 | 7.5 C | -0.89 C |
| 2006 | 9.1 C | +0.73 C |
| 2007 | 9.1 C | +0.75 C |
| 2008 | 7.7 C | -0.70 C |
| 2009 | 7.3 C | -1.06 C |
| 2010 | 7.7 C | -0.66 C |
| 2011 | 7.4 C | -0.96 C |
| 2012 | 9.9 C | +1.57 C |
| 2013 | 7.6 C | -0.79 C |
| 2014 | 7.8 C | -0.57 C |
| 2015 | 9.0 C | +0.63 C |
| 2016 | 8.8 C | +0.44 C |
| 2017 | 7.6 C | -0.79 C |
| 2018 | 7.7 C | -0.63 C |
| 2019 | 6.3 C | -2.05 C |
| 2020 | 8.0 C | -0.41 C |
| 2021 | 9.3 C | +0.90 C |
| 2022 | 7.9 C | -0.50 C |
| 2023 | 6.4 C | -1.93 C |
| 2024 | 9.4 C | +1.02 C |
| 2025 | 9.5 C | +1.15 C |
The fitted trend in annual mean temperature here over 1949 to 2025 is -0.07 C (-0.18 to 0.04) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.1 F (-0.3 to 0.1) per decade. The slope is a straight line fitted to 60 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | -0.07 C (-0.18 to 0.04) per decade | -0.1 F (-0.3 to 0.1) per decade | 1949 to 2025 | 60 | Not clearly different from zero |
| Mean daily maximum | -0.01 C (-0.13 to 0.12) per decade | -0.01 F (-0.23 to 0.21) per decade | 1949 to 2025 | 60 | Not clearly different from zero |
| Mean daily minimum | -0.14 C (-0.24 to -0.04) per decade | -0.3 F (-0.4 to -0.1) per decade | 1949 to 2025 | 60 | 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
1948 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 42.2 C (108.0 F) | 1954 | 37.8 C (100.0 F) | 79 |
| Coldest night (TNn) | -39.4 C (-38.9 F) | 1979 | -27.8 C (-18.0 F) | 79 |
| Wettest day (Rx1day) | 63.8 mm (2.5 in) | 1964 | 24.1 mm (0.9 in) | 79 |
| Wettest five days (Rx5day) | 110.5 mm (4.4 in) | 2008 | 40.2 mm (1.6 in) | 79 |
| Longest dry spell (CDD) | 76 days | 1965 | 41 days | 79 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1948 | 36.7 C (98.1 F) |
| 1949 | 38.3 C (100.9 F) |
| 1950 | 35.6 C (96.1 F) |
| 1951 | 37.2 C (99.0 F) |
| 1952 | 36.1 C (97.0 F) |
| 1953 | 38.9 C (102.0 F) |
| 1954 | 42.2 C (108.0 F) |
| 1955 | 39.4 C (102.9 F) |
| 1956 | 37.2 C (99.0 F) |
| 1957 | 36.7 C (98.1 F) |
| 1958 | 35.6 C (96.1 F) |
| 1959 | 38.9 C (102.0 F) |
| 1960 | 39.4 C (102.9 F) |
| 1961 | 38.9 C (102.0 F) |
| 1962 | 36.1 C (97.0 F) |
| 1963 | 36.7 C (98.1 F) |
| 1964 | 37.8 C (100.0 F) |
| 1965 | 36.1 C (97.0 F) |
| 1966 | 37.8 C (100.0 F) |
| 1967 | 35.6 C (96.1 F) |
| 1968 | 36.7 C (98.1 F) |
| 1969 | 38.3 C (100.9 F) |
| 1970 | 37.2 C (99.0 F) |
| 1971 | 37.8 C (100.0 F) |
| 1972 | 37.8 C (100.0 F) |
| 1973 | 37.8 C (100.0 F) |
| 1974 | 37.2 C (99.0 F) |
| 1975 | 36.7 C (98.1 F) |
| 1976 | 37.8 C (100.0 F) |
| 1977 | 37.2 C (99.0 F) |
| 1978 | 36.7 C (98.1 F) |
| 1979 | 40.0 C (104.0 F) |
| 1980 | 36.7 C (98.1 F) |
| 1981 | 38.3 C (100.9 F) |
| 1982 | 38.3 C (100.9 F) |
| 1983 | 38.9 C (102.0 F) |
| 1984 | 37.8 C (100.0 F) |
| 1985 | 37.8 C (100.0 F) |
| 1986 | 36.7 C (98.1 F) |
| 1987 | 36.7 C (98.1 F) |
| 1988 | 40.0 C (104.0 F) |
| 1989 | 40.6 C (105.1 F) |
| 1990 | 38.9 C (102.0 F) |
| 1991 | 37.8 C (100.0 F) |
| 1992 | 36.1 C (97.0 F) |
| 1993 | 36.7 C (98.1 F) |
| 1994 | 37.2 C (99.0 F) |
| 1995 | 38.3 C (100.9 F) |
| 1996 | 38.9 C (102.0 F) |
| 1997 | 37.2 C (99.0 F) |
| 1998 | 40.6 C (105.1 F) |
| 1999 | 37.8 C (100.0 F) |
| 2000 | 37.2 C (99.0 F) |
| 2001 | 37.8 C (100.0 F) |
| 2002 | 39.4 C (102.9 F) |
| 2003 | 38.3 C (100.9 F) |
| 2004 | 36.1 C (97.0 F) |
| 2005 | 38.9 C (102.0 F) |
| 2006 | 40.6 C (105.1 F) |
| 2007 | 38.9 C (102.0 F) |
| 2008 | 38.3 C (100.9 F) |
| 2009 | 35.6 C (96.1 F) |
| 2010 | 37.8 C (100.0 F) |
| 2011 | 37.8 C (100.0 F) |
| 2012 | 39.4 C (102.9 F) |
| 2013 | 37.2 C (99.0 F) |
| 2014 | 38.3 C (100.9 F) |
| 2015 | 36.7 C (98.1 F) |
| 2016 | 38.3 C (100.9 F) |
| 2017 | 37.2 C (99.0 F) |
| 2018 | 39.4 C (102.9 F) |
| 2019 | 38.3 C (100.9 F) |
| 2020 | 37.8 C (100.0 F) |
| 2021 | 40.0 C (104.0 F) |
| 2022 | 39.4 C (102.9 F) |
| 2023 | 36.7 C (98.1 F) |
| 2024 | 39.4 C (102.9 F) |
| 2025 | 39.4 C (102.9 F) |
| 2026 | 41.7 C (107.1 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1948 | -31.1 C (-24.0 F) |
| 1949 | -37.2 C (-35.0 F) |
| 1950 | -34.4 C (-29.9 F) |
| 1951 | -31.7 C (-25.1 F) |
| 1952 | -32.2 C (-26.0 F) |
| 1953 | -20.0 C (-4.0 F) |
| 1954 | -20.0 C (-4.0 F) |
| 1955 | -23.3 C (-9.9 F) |
| 1956 | -35.6 C (-32.1 F) |
| 1957 | -29.4 C (-20.9 F) |
| 1958 | -16.7 C (1.9 F) |
| 1959 | -22.2 C (-8.0 F) |
| 1960 | -27.8 C (-18.0 F) |
| 1961 | -27.8 C (-18.0 F) |
| 1962 | -38.3 C (-36.9 F) |
| 1963 | -35.0 C (-31.0 F) |
| 1964 | -27.8 C (-18.0 F) |
| 1965 | -23.3 C (-9.9 F) |
| 1966 | -25.6 C (-14.1 F) |
| 1967 | -24.4 C (-11.9 F) |
| 1968 | -27.8 C (-18.0 F) |
| 1969 | -20.6 C (-5.1 F) |
| 1970 | -23.9 C (-11.0 F) |
| 1971 | -25.0 C (-13.0 F) |
| 1972 | -33.3 C (-27.9 F) |
| 1973 | -33.3 C (-27.9 F) |
| 1974 | -26.7 C (-16.1 F) |
| 1975 | -26.7 C (-16.1 F) |
| 1976 | -29.4 C (-20.9 F) |
| 1977 | -26.1 C (-15.0 F) |
| 1978 | -37.8 C (-36.0 F) |
| 1979 | -39.4 C (-38.9 F) |
| 1980 | -31.1 C (-24.0 F) |
| 1981 | -26.1 C (-15.0 F) |
| 1982 | -30.6 C (-23.1 F) |
| 1983 | -36.1 C (-33.0 F) |
| 1984 | -33.9 C (-29.0 F) |
| 1985 | -33.9 C (-29.0 F) |
| 1986 | -28.3 C (-18.9 F) |
| 1987 | -24.4 C (-11.9 F) |
| 1988 | -23.9 C (-11.0 F) |
| 1989 | -31.7 C (-25.1 F) |
| 1990 | -34.4 C (-29.9 F) |
| 1991 | -24.4 C (-11.9 F) |
| 1992 | -23.3 C (-9.9 F) |
| 1993 | -34.4 C (-29.9 F) |
| 1994 | -22.2 C (-8.0 F) |
| 1995 | -24.4 C (-11.9 F) |
| 1996 | -26.1 C (-15.0 F) |
| 1997 | -22.8 C (-9.0 F) |
| 1998 | -30.0 C (-22.0 F) |
| 1999 | -18.3 C (-0.9 F) |
| 2000 | -23.3 C (-9.9 F) |
| 2001 | -30.6 C (-23.1 F) |
| 2002 | -24.4 C (-11.9 F) |
| 2003 | -26.1 C (-15.0 F) |
| 2004 | -28.9 C (-20.0 F) |
| 2005 | -21.7 C (-7.1 F) |
| 2006 | -28.9 C (-20.0 F) |
| 2007 | -27.2 C (-17.0 F) |
| 2008 | -30.0 C (-22.0 F) |
| 2009 | -28.9 C (-20.0 F) |
| 2010 | -27.8 C (-18.0 F) |
| 2011 | -28.3 C (-18.9 F) |
| 2012 | -28.9 C (-20.0 F) |
| 2013 | -28.3 C (-18.9 F) |
| 2014 | -29.4 C (-20.9 F) |
| 2015 | -30.0 C (-22.0 F) |
| 2016 | -23.9 C (-11.0 F) |
| 2017 | -32.2 C (-26.0 F) |
| 2018 | -27.2 C (-17.0 F) |
| 2019 | -25.6 C (-14.1 F) |
| 2020 | -26.7 C (-16.1 F) |
| 2021 | -23.9 C (-11.0 F) |
| 2022 | -32.2 C (-26.0 F) |
| 2023 | -37.8 C (-36.0 F) |
| 2024 | -30.6 C (-23.1 F) |
| 2025 | -27.8 C (-18.0 F) |
| 2026 | -21.7 C (-7.1 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1948 | 16.3 mm (0.6 in) |
| 1949 | 23.1 mm (0.9 in) |
| 1950 | 24.1 mm (0.9 in) |
| 1951 | 13.0 mm (0.5 in) |
| 1952 | 29.2 mm (1.1 in) |
| 1953 | 27.9 mm (1.1 in) |
| 1954 | 12.7 mm (0.5 in) |
| 1955 | 20.6 mm (0.8 in) |
| 1956 | 24.9 mm (1.0 in) |
| 1957 | 57.2 mm (2.3 in) |
| 1958 | 19.1 mm (0.8 in) |
| 1959 | 20.3 mm (0.8 in) |
| 1960 | 14.0 mm (0.6 in) |
| 1961 | 20.3 mm (0.8 in) |
| 1962 | 18.3 mm (0.7 in) |
| 1963 | 56.4 mm (2.2 in) |
| 1964 | 63.8 mm (2.5 in) |
| 1965 | 23.9 mm (0.9 in) |
| 1966 | 12.4 mm (0.5 in) |
| 1967 | 18.8 mm (0.7 in) |
| 1968 | 25.1 mm (1.0 in) |
| 1969 | 24.9 mm (1.0 in) |
| 1970 | 22.4 mm (0.9 in) |
| 1971 | 31.8 mm (1.3 in) |
| 1972 | 14.5 mm (0.6 in) |
| 1973 | 45.7 mm (1.8 in) |
| 1974 | 20.3 mm (0.8 in) |
| 1975 | 29.0 mm (1.1 in) |
| 1976 | 50.8 mm (2.0 in) |
| 1977 | 27.9 mm (1.1 in) |
| 1978 | 50.8 mm (2.0 in) |
| 1979 | 17.0 mm (0.7 in) |
| 1980 | 27.9 mm (1.1 in) |
| 1981 | 21.3 mm (0.8 in) |
| 1982 | 31.8 mm (1.3 in) |
| 1983 | 12.7 mm (0.5 in) |
| 1984 | 22.1 mm (0.9 in) |
| 1985 | 24.1 mm (0.9 in) |
| 1986 | 17.8 mm (0.7 in) |
| 1987 | 22.1 mm (0.9 in) |
| 1988 | 20.3 mm (0.8 in) |
| 1989 | 27.9 mm (1.1 in) |
| 1990 | 17.8 mm (0.7 in) |
| 1991 | 15.7 mm (0.6 in) |
| 1992 | 18.8 mm (0.7 in) |
| 1993 | 32.8 mm (1.3 in) |
| 1994 | 12.7 mm (0.5 in) |
| 1995 | 19.3 mm (0.8 in) |
| 1996 | 7.6 mm (0.30 in) |
| 1997 | 38.9 mm (1.5 in) |
| 1998 | 26.9 mm (1.1 in) |
| 1999 | 33.5 mm (1.3 in) |
| 2000 | 23.4 mm (0.9 in) |
| 2001 | 26.4 mm (1.0 in) |
| 2002 | 21.6 mm (0.9 in) |
| 2003 | 50.8 mm (2.0 in) |
| 2004 | 12.7 mm (0.5 in) |
| 2005 | 26.4 mm (1.0 in) |
| 2006 | 23.4 mm (0.9 in) |
| 2007 | 49.5 mm (1.9 in) |
| 2008 | 49.5 mm (1.9 in) |
| 2009 | 33.0 mm (1.3 in) |
| 2010 | 20.6 mm (0.8 in) |
| 2011 | 33.5 mm (1.3 in) |
| 2012 | 9.9 mm (0.39 in) |
| 2013 | 39.1 mm (1.5 in) |
| 2014 | 19.3 mm (0.8 in) |
| 2015 | 30.7 mm (1.2 in) |
| 2016 | 47.0 mm (1.9 in) |
| 2017 | 23.9 mm (0.9 in) |
| 2018 | 35.3 mm (1.4 in) |
| 2019 | 50.8 mm (2.0 in) |
| 2020 | 25.4 mm (1.0 in) |
| 2021 | 16.5 mm (0.6 in) |
| 2022 | 31.8 mm (1.3 in) |
| 2023 | 38.1 mm (1.5 in) |
| 2024 | 19.6 mm (0.8 in) |
| 2025 | 26.7 mm (1.1 in) |
| 2026 | 41.7 mm (1.6 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1948 | 17.6 mm (0.7 in) |
| 1949 | 29.7 mm (1.2 in) |
| 1950 | 25.9 mm (1.0 in) |
| 1951 | 22.3 mm (0.9 in) |
| 1952 | 53.3 mm (2.1 in) |
| 1953 | 33.3 mm (1.3 in) |
| 1954 | 15.2 mm (0.6 in) |
| 1955 | 48.1 mm (1.9 in) |
| 1956 | 44.5 mm (1.8 in) |
| 1957 | 70.9 mm (2.8 in) |
| 1958 | 37.1 mm (1.5 in) |
| 1959 | 28.6 mm (1.1 in) |
| 1960 | 19.7 mm (0.8 in) |
| 1961 | 42.6 mm (1.7 in) |
| 1962 | 37.8 mm (1.5 in) |
| 1963 | 70.2 mm (2.8 in) |
| 1964 | 75.4 mm (3.0 in) |
| 1965 | 40.4 mm (1.6 in) |
| 1966 | 21.6 mm (0.9 in) |
| 1967 | 47.3 mm (1.9 in) |
| 1968 | 45.8 mm (1.8 in) |
| 1969 | 44.7 mm (1.8 in) |
| 1970 | 36.1 mm (1.4 in) |
| 1971 | 40.2 mm (1.6 in) |
| 1972 | 21.3 mm (0.8 in) |
| 1973 | 61.8 mm (2.4 in) |
| 1974 | 44.4 mm (1.7 in) |
| 1975 | 58.0 mm (2.3 in) |
| 1976 | 68.7 mm (2.7 in) |
| 1977 | 54.3 mm (2.1 in) |
| 1978 | 62.5 mm (2.5 in) |
| 1979 | 27.0 mm (1.1 in) |
| 1980 | 31.7 mm (1.2 in) |
| 1981 | 30.8 mm (1.2 in) |
| 1982 | 39.8 mm (1.6 in) |
| 1983 | 29.4 mm (1.2 in) |
| 1984 | 27.0 mm (1.1 in) |
| 1985 | 27.9 mm (1.1 in) |
| 1986 | 23.4 mm (0.9 in) |
| 1987 | 39.1 mm (1.5 in) |
| 1988 | 37.1 mm (1.5 in) |
| 1989 | 40.6 mm (1.6 in) |
| 1990 | 26.0 mm (1.0 in) |
| 1991 | 40.1 mm (1.6 in) |
| 1992 | 31.0 mm (1.2 in) |
| 1993 | 44.8 mm (1.8 in) |
| 1994 | 14.7 mm (0.6 in) |
| 1995 | 28.0 mm (1.1 in) |
| 1996 | 12.4 mm (0.5 in) |
| 1997 | 41.2 mm (1.6 in) |
| 1998 | 41.5 mm (1.6 in) |
| 1999 | 49.6 mm (2.0 in) |
| 2000 | 24.4 mm (1.0 in) |
| 2001 | 27.7 mm (1.1 in) |
| 2002 | 29.7 mm (1.2 in) |
| 2003 | 59.4 mm (2.3 in) |
| 2004 | 26.2 mm (1.0 in) |
| 2005 | 55.6 mm (2.2 in) |
| 2006 | 32.0 mm (1.3 in) |
| 2007 | 69.3 mm (2.7 in) |
| 2008 | 110.5 mm (4.4 in) |
| 2009 | 40.9 mm (1.6 in) |
| 2010 | 51.9 mm (2.0 in) |
| 2011 | 58.7 mm (2.3 in) |
| 2012 | 9.9 mm (0.39 in) |
| 2013 | 45.2 mm (1.8 in) |
| 2014 | 25.2 mm (1.0 in) |
| 2015 | 50.8 mm (2.0 in) |
| 2016 | 77.5 mm (3.1 in) |
| 2017 | 46.5 mm (1.8 in) |
| 2018 | 41.6 mm (1.6 in) |
| 2019 | 65.3 mm (2.6 in) |
| 2020 | 26.7 mm (1.1 in) |
| 2021 | 26.2 mm (1.0 in) |
| 2022 | 43.5 mm (1.7 in) |
| 2023 | 42.6 mm (1.7 in) |
| 2024 | 21.9 mm (0.9 in) |
| 2025 | 51.8 mm (2.0 in) |
| 2026 | 44.5 mm (1.8 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1948 | 32 days |
| 1949 | 49 days |
| 1950 | 63 days |
| 1951 | 63 days |
| 1952 | 69 days |
| 1953 | 33 days |
| 1954 | 66 days |
| 1955 | 32 days |
| 1956 | 43 days |
| 1957 | 62 days |
| 1958 | 35 days |
| 1959 | 32 days |
| 1960 | 41 days |
| 1961 | 42 days |
| 1962 | 45 days |
| 1963 | 53 days |
| 1964 | 50 days |
| 1965 | 76 days |
| 1966 | 42 days |
| 1967 | 44 days |
| 1968 | 42 days |
| 1969 | 35 days |
| 1970 | 67 days |
| 1971 | 38 days |
| 1972 | 31 days |
| 1973 | 34 days |
| 1974 | 28 days |
| 1975 | 32 days |
| 1976 | 66 days |
| 1977 | 48 days |
| 1978 | 34 days |
| 1979 | 65 days |
| 1980 | 33 days |
| 1981 | 34 days |
| 1982 | 53 days |
| 1983 | 27 days |
| 1984 | 36 days |
| 1985 | 35 days |
| 1986 | 23 days |
| 1987 | 38 days |
| 1988 | 47 days |
| 1989 | 32 days |
| 1990 | 36 days |
| 1991 | 38 days |
| 1992 | 50 days |
| 1993 | 34 days |
| 1994 | 32 days |
| 1995 | 32 days |
| 1996 | 49 days |
| 1997 | 37 days |
| 1998 | 36 days |
| 1999 | 39 days |
| 2000 | 30 days |
| 2001 | 47 days |
| 2002 | 58 days |
| 2003 | 41 days |
| 2004 | 38 days |
| 2005 | 42 days |
| 2006 | 43 days |
| 2007 | 32 days |
| 2008 | 68 days |
| 2009 | 42 days |
| 2010 | 64 days |
| 2011 | 41 days |
| 2012 | 56 days |
| 2013 | 34 days |
| 2014 | 51 days |
| 2015 | 54 days |
| 2016 | 41 days |
| 2017 | 31 days |
| 2018 | 46 days |
| 2019 | 55 days |
| 2020 | 49 days |
| 2021 | 30 days |
| 2022 | 21 days |
| 2023 | 28 days |
| 2024 | 46 days |
| 2025 | 41 days |
| 2026 | 49 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
60 years with a frostAcross 60 years with a frost, the median last spring frost at Boysen Dam falls on 6 May and the median first autumn frost on 8 October, which leaves a median of 154 days between them.
In 1989 to 2025 the median growing season was 154 days. That is 1 day fewer than in 1949 to 1988.
Fitted over all years, the growing season changes by +0.1 days per decade at this station.
| Measure | Median, all years | Earliest period (1949 to 1988) | Recent period (1989 to 2025) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 6 May | 4 May | 7 May | 3 days later | +0.5 days per decade |
| First autumn frost | 8 October | 7 October | 9 October | 2 days later | +0.6 days per decade |
| Growing days | 154 days | 155 days | 154 days | 1 day fewer | +0.1 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
74 years, 1949 to 2025A day with at least 24.6 mm (1.0 in) of rain is expected about once in 2 years. A day with at least 73.1 mm (2.9 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 24.6 mm (1.0 in) | |
| 5 years | 35.3 mm (1.4 in) | |
| 10 years | 43.2 mm (1.7 in) | |
| 25 years | 54.2 mm (2.1 in) | |
| 50 years | 63.3 mm (2.5 in) | |
| 100 years | 73.1 mm (2.9 in) | Longer than the 74 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, 74 years of values from 1949 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: 63.8 mm (2.5 in) in 1964; 57.2 mm (2.3 in) in 1957; 56.4 mm (2.2 in) in 1963.
Station Changes
1 suspectedOne change was suspected in the annual mean temperature of Boysen Dam, at 1973. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1973 ran 0.4 C (0.6 F) lower than in the years before (possible change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 1973 | -0.3 | -0.6 | 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, Boysen Dam had a mean temperature of 8.2 C (46.7 F) and 240.3 mm (9.5 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Dinosaur Nm-Quarry Area (United States, 343 km away), Rangely 1E (United States, 372 km away) and Powderville 8 NNE (United States, 368 km away).
| Twin station | Country | Distance away | Mean temperature, 1961-1990 | Rain a year, 1961-1990 | Climate difference |
|---|---|---|---|---|---|
| Dinosaur Nm-Quarry Area | United States | 343 km (213 mi) | 8.6 C (47.4 F) | 212.7 mm (8.4 in) | 1.05 |
| Rangely 1E | United States | 372 km (231 mi) | 8.0 C (46.4 F) | 224.8 mm (8.9 in) | 1.09 |
| Powderville 8 NNE | United States | 368 km (229 mi) | 7.7 C (45.8 F) | 330.5 mm (13.0 in) | 1.13 |
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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-14).