Promontory Weather Records (USS0011R10S)
Record envelope, standing records and threshold days for Promontory (USS0011R10S), Arizona, United States, with 47 years of record.
Key Facts for Promontory
- Promontory (USS0011R10S) is a weather station in Arizona, United States at 34.37 latitude and -111.01 longitude, 2,417 m (7,930 ft) above sea level.
- The station reports from 1980 to 2026, 47 years of record.
- 1,464 records set at Promontory still stand.
- Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
- Promontory tied a daily record precipitation of 35.6 mm (1.4 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: Arizona, United States, 34.37 latitude, -111.01 longitude.
- Elevation: 2,417 m (7,930 ft).
- Period of record: 1980 to 2026, 47 years.
- Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
15 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 16.8 C (62.2 F) | -18.7 C (-1.7 F) | 11.5 C (52.7 F) | -11.0 C (12.2 F) |
| Feb | 18.4 C (65.1 F) | -27.2 C (-17.0 F) | 17.4 C (63.3 F) | -9.1 C (15.6 F) |
| Mar | 25.7 C (78.3 F) | -24.5 C (-12.1 F) | 25.7 C (78.3 F) | -6.6 C (20.1 F) |
| Apr | 26.4 C (79.5 F) | -10.5 C (13.1 F) | 18.0 C (64.4 F) | -2.4 C (27.7 F) |
| May | 33.2 C (91.8 F) | -5.5 C (22.1 F) | 25.0 C (77.0 F) | 0.1 C (32.2 F) |
| Jun | 34.9 C (94.8 F) | -1.0 C (30.2 F) | 29.5 C (85.1 F) | 9.3 C (48.7 F) |
| Jul | 37.1 C (98.8 F) | -0.8 C (30.6 F) | 29.2 C (84.6 F) | 9.7 C (49.5 F) |
| Aug | 32.8 C (91.0 F) | 1.1 C (34.0 F) | 28.8 C (83.8 F) | 10.7 C (51.3 F) |
| Sep | 32.3 C (90.1 F) | -5.1 C (22.8 F) | 27.5 C (81.5 F) | 2.9 C (37.2 F) |
| Oct | 26.9 C (80.4 F) | -11.7 C (10.9 F) | 21.1 C (70.0 F) | 0.1 C (32.2 F) |
| Nov | 25.1 C (77.2 F) | -14.5 C (5.9 F) | n/a | n/a |
| Dec | 18.7 C (65.7 F) | -21.8 C (-7.2 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1983 | 79 |
| 1984 | 73 |
| 1985 | 67 |
| 1986 | 26 |
| 1987 | 78 |
| 1988 | 69 |
| 1989 | 24 |
| 1990 | 33 |
| 1991 | 18 |
| 1992 | 12 |
| 1993 | 16 |
| 1994 | 29 |
| 1995 | 30 |
| 1996 | 39 |
| 1997 | 16 |
| 1998 | 17 |
| 1999 | 18 |
| 2000 | 39 |
| 2001 | 25 |
| 2002 | 30 |
| 2003 | 20 |
| 2004 | 15 |
| 2005 | 15 |
| 2006 | 16 |
| 2007 | 38 |
| 2008 | 21 |
| 2009 | 26 |
| 2010 | 15 |
| 2011 | 32 |
| 2012 | 25 |
| 2013 | 24 |
| 2014 | 16 |
| 2015 | 35 |
| 2016 | 32 |
| 2017 | 58 |
| 2018 | 41 |
| 2019 | 20 |
| 2020 | 93 |
| 2021 | 32 |
| 2022 | 22 |
| 2023 | 29 |
| 2024 | 25 |
| 2025 | 44 |
| 2026 | 32 |
All-Time Record Progression
3 new records| Date | Kind | Detail |
|---|---|---|
| 2017-06-19 | Record high minimum temperature | Record high minimum temperature 20.6 C (69.1 F) |
| 2017-06-21 | Record high minimum temperature | Record high minimum temperature 21.3 C (70.3 F) |
| 2020-07-31 | Record high minimum temperature | Record high minimum temperature 22.2 C (72.0 F) |
Wettest Day of Each Month
Jan: 142.2 mm (5.6 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 142.2 mm (5.6 in) | 21 January 2010 |
| Feb | 101.6 mm (4.0 in) | 14 February 1995 |
| Mar | 124.5 mm (4.9 in) | 1 March 1991 |
| Apr | 66.0 mm (2.6 in) | 2 April 1999 |
| May | 38.1 mm (1.5 in) | 20 May 1987 |
| Jun | 33.0 mm (1.3 in) | 30 June 2021 |
| Jul | 81.3 mm (3.2 in) | 20 July 2026 |
| Aug | 139.7 mm (5.5 in) | 23 August 1992 |
| Sep | 83.8 mm (3.3 in) | 19 September 2004 |
| Oct | 58.4 mm (2.3 in) | 2 October 2018 |
| Nov | 86.4 mm (3.4 in) | 22 November 2013 |
| Dec | 104.1 mm (4.1 in) | 7 December 2009 |
Period of Record Coverage
1983 to 2026| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1983 | 218 | 60% | No |
| 1984 | 357 | 98% | Yes |
| 1985 | 363 | 99% | Yes |
| 1986 | 213 | 58% | No |
| 1987 | 316 | 87% | No |
| 1988 | 353 | 96% | Yes |
| 1989 | 311 | 85% | No |
| 1990 | 218 | 60% | No |
| 1991 | 365 | 100% | Yes |
| 1992 | 366 | 100% | Yes |
| 1993 | 261 | 72% | No |
| 1994 | 297 | 81% | No |
| 1995 | 365 | 100% | Yes |
| 1996 | 366 | 100% | Yes |
| 1997 | 329 | 90% | Yes |
| 1998 | 363 | 99% | Yes |
| 1999 | 363 | 99% | Yes |
| 2000 | 366 | 100% | Yes |
| 2001 | 298 | 82% | No |
| 2002 | 365 | 100% | Yes |
| 2003 | 195 | 53% | No |
| 2004 | 341 | 93% | Yes |
| 2005 | 365 | 100% | Yes |
| 2006 | 338 | 93% | Yes |
| 2007 | 364 | 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 | 359 | 98% | Yes |
| 2017 | 355 | 97% | Yes |
| 2018 | 362 | 99% | Yes |
| 2019 | 365 | 100% | Yes |
| 2020 | 365 | 100% | Yes |
| 2021 | 365 | 100% | Yes |
| 2022 | 365 | 100% | Yes |
| 2023 | 352 | 96% | Yes |
| 2024 | 362 | 99% | Yes |
| 2025 | 364 | 100% | Yes |
| 2026 | 287 | 79% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 13 October 2026 | Promontory, US | daily rain (Tie, Provisional) | 35.6 mm (1.4 in) | tie | 0 years | 1 of 100 (Routine) |
| 12 October 2026 | Promontory, US | daily rain (Provisional) | 27.9 mm (1.1 in) | 7.6 mm (0.30 in) | 13 years | 14 of 100 (Routine) |
| 30 September 2026 | Promontory, US | daily rain (Provisional) | 10.2 mm (0.4 in) | 2.6 mm (0.10 in) | 21 years | 12 of 100 (Routine) |
| 29 September 2026 | Promontory, US | daily rain (Provisional) | 45.7 mm (1.8 in) | 33.0 mm (1.3 in) | 41 years | 44 of 100 (Notable) |
| 17 September 2026 | Promontory, US | daily rain (Provisional) | 33.0 mm (1.3 in) | 22.8 mm (0.9 in) | 40 years | 35 of 100 (Notable) |
| 10 September 2026 | Promontory, US | daily high max (Provisional) | 27.5 C (81.5 F) | 1.2 C (2.2 F) | 24 years | 13 of 100 (Routine) |
| 27 August 2026 | Promontory, US | daily high min (Provisional) | 19.1 C (66.4 F) | 1.6 C (2.9 F) | 16 years | 14 of 100 (Routine) |
| 26 August 2026 | Promontory, US | daily high min (Provisional) | 18.8 C (65.8 F) | 2.4 C (4.3 F) | 8 years | 13 of 100 (Routine) |
| 18 August 2026 | Promontory, US | daily high min | 17.1 C (62.8 F) | 0.1 C (0.2 F) | 11 years | 7 of 100 (Routine) |
| 3 August 2026 | Promontory, US | daily high min | 18.6 C (65.5 F) | 0.2 C (0.4 F) | 31 years | 13 of 100 (Routine) |
| 2 August 2026 | Promontory, US | daily high min | 18.5 C (65.3 F) | 1.5 C (2.7 F) | 31 years | 17 of 100 (Routine) |
| 1 August 2026 | Promontory, US | monthly high min | 21.4 C (70.5 F) | 1.3 C (2.3 F) | 0 years | 18 of 100 (Routine) |
| 24 July 2026 | Promontory, US | daily high min (Tie) | 18.6 C (65.5 F) | tie | 8 years | 1 of 100 (Routine) |
| 21 July 2026 | Promontory, US | daily rain | 53.3 mm (2.1 in) | 10.1 mm (0.4 in) | 17 years | 20 of 100 (Routine) |
| 20 July 2026 | Promontory, US | monthly rain | 81.3 mm (3.2 in) | 22.9 mm (0.9 in) | 23 years | 45 of 100 (Notable) |
| 17 July 2026 | Promontory, US | daily rain (Tie) | 10.2 mm (0.4 in) | tie | 21 years | 2 of 100 (Routine) |
| 29 May 2026 | Promontory, US | daily rain (Tie) | 2.5 mm (0.10 in) | tie | 40 years | 4 of 100 (Routine) |
| 11 May 2026 | Promontory, US | daily high min | 13.8 C (56.8 F) | 0.5 C (0.9 F) | 29 years | 13 of 100 (Routine) |
| 13 April 2026 | Promontory, US | daily rain | 10.2 mm (0.4 in) | 5.1 mm (0.20 in) | 37 years | 19 of 100 (Routine) |
| 3 April 2026 | Promontory, US | daily rain | 45.7 mm (1.8 in) | 17.8 mm (0.7 in) | 21 years | 27 of 100 (Routine) |
Climate Trend
30 complete years, 1984 to 2025| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1984 | 4.3 C | -5.14 C |
| 1985 | 4.6 C | -4.85 C |
| 1988 | 5.1 C | -4.32 C |
| 1991 | 8.2 C | -1.16 C |
| 1992 | 8.2 C | -1.16 C |
| 1995 | 9.3 C | -0.08 C |
| 1996 | 9.6 C | +0.18 C |
| 1998 | 8.3 C | -1.13 C |
| 1999 | 9.2 C | -0.21 C |
| 2000 | 9.9 C | +0.46 C |
| 2002 | 9.6 C | +0.20 C |
| 2005 | 9.6 C | +0.23 C |
| 2007 | 10.4 C | +0.95 C |
| 2008 | 9.7 C | +0.27 C |
| 2009 | 9.9 C | +0.53 C |
| 2010 | 9.5 C | +0.09 C |
| 2011 | 9.6 C | +0.20 C |
| 2012 | 11.0 C | +1.58 C |
| 2013 | 9.6 C | +0.21 C |
| 2014 | 10.8 C | +1.38 C |
| 2015 | 10.3 C | +0.86 C |
| 2016 | 10.8 C | +1.39 C |
| 2017 | 11.5 C | +2.12 C |
| 2018 | 11.0 C | +1.59 C |
| 2019 | 9.8 C | +0.39 C |
| 2020 | 11.4 C | +2.01 C |
| 2021 | 10.7 C | +1.26 C |
| 2022 | 10.0 C | +0.64 C |
| 2024 | 10.1 C | +0.71 C |
| 2025 | 10.3 C | +0.89 C |
The annual mean temperature here has risen by 1.2 C (0.9 to 1.6) per decade over 1984 to 2025. In Fahrenheit: 2.2 F (1.6 to 2.8) per decade. The slope is a straight line fitted to 30 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 1.2 C (0.9 to 1.6) per decade | 2.2 F (1.6 to 2.8) per decade | 1984 to 2025 | 30 | Rise |
| Mean daily maximum | 1.3 C (0.8 to 1.8) per decade | 2.3 F (1.5 to 3.2) per decade | 1984 to 2025 | 30 | Rise |
| Mean daily minimum | 1.2 C (0.9 to 1.4) per decade | 2.1 F (1.7 to 2.5) per decade | 1984 to 2025 | 30 | 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
1980 to 2026| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 37.1 C (98.8 F) | 1987 | 31.8 C (89.2 F) | 44 |
| Coldest night (TNn) | -27.2 C (-17.0 F) | 1989 | -14.6 C (5.7 F) | 44 |
| Wettest day (Rx1day) | 142.2 mm (5.6 in) | 2010 | 67.3 mm (2.6 in) | 46 |
| Wettest five days (Rx5day) | 320.0 mm (12.6 in) | 2010 | 128.3 mm (5.1 in) | 46 |
| Longest dry spell (CDD) | 107 days | 2017 | 44 days | 46 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1980 | n/a |
| 1981 | n/a |
| 1983 | 29.0 C (84.2 F) |
| 1984 | 23.2 C (73.8 F) |
| 1985 | 26.9 C (80.4 F) |
| 1986 | 23.6 C (74.5 F) |
| 1987 | 37.1 C (98.8 F) |
| 1988 | 23.7 C (74.7 F) |
| 1989 | 34.2 C (93.6 F) |
| 1990 | 24.7 C (76.5 F) |
| 1991 | 32.0 C (89.6 F) |
| 1992 | 30.1 C (86.2 F) |
| 1993 | 24.4 C (75.9 F) |
| 1994 | 33.5 C (92.3 F) |
| 1995 | 33.5 C (92.3 F) |
| 1996 | 31.8 C (89.2 F) |
| 1997 | 32.5 C (90.5 F) |
| 1998 | 33.3 C (91.9 F) |
| 1999 | 32.4 C (90.3 F) |
| 2000 | 33.3 C (91.9 F) |
| 2001 | 32.7 C (90.9 F) |
| 2002 | 33.2 C (91.8 F) |
| 2003 | 24.7 C (76.5 F) |
| 2004 | 29.5 C (85.1 F) |
| 2005 | 31.8 C (89.2 F) |
| 2006 | 31.5 C (88.7 F) |
| 2007 | 34.4 C (93.9 F) |
| 2008 | 30.4 C (86.7 F) |
| 2009 | 30.7 C (87.3 F) |
| 2010 | 31.0 C (87.8 F) |
| 2011 | 31.8 C (89.2 F) |
| 2012 | 31.6 C (88.9 F) |
| 2013 | 33.9 C (93.0 F) |
| 2014 | 30.2 C (86.4 F) |
| 2015 | 30.2 C (86.4 F) |
| 2016 | 34.6 C (94.3 F) |
| 2017 | 32.9 C (91.2 F) |
| 2018 | 32.7 C (90.9 F) |
| 2019 | 31.9 C (89.4 F) |
| 2020 | 33.4 C (92.1 F) |
| 2021 | 34.9 C (94.8 F) |
| 2022 | 30.2 C (86.4 F) |
| 2023 | 32.3 C (90.1 F) |
| 2024 | 29.9 C (85.8 F) |
| 2025 | 30.7 C (87.3 F) |
| 2026 | 29.5 C (85.1 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1980 | n/a |
| 1981 | n/a |
| 1983 | -11.8 C (10.8 F) |
| 1984 | -15.1 C (4.8 F) |
| 1985 | -22.4 C (-8.3 F) |
| 1986 | -18.1 C (-0.6 F) |
| 1987 | -24.5 C (-12.1 F) |
| 1988 | -18.7 C (-1.7 F) |
| 1989 | -27.2 C (-17.0 F) |
| 1990 | -21.8 C (-7.2 F) |
| 1991 | -12.9 C (8.8 F) |
| 1992 | -12.8 C (9.0 F) |
| 1993 | -11.4 C (11.5 F) |
| 1994 | -17.6 C (0.3 F) |
| 1995 | -11.1 C (12.0 F) |
| 1996 | -15.2 C (4.6 F) |
| 1997 | -14.7 C (5.5 F) |
| 1998 | -13.3 C (8.1 F) |
| 1999 | -14.7 C (5.5 F) |
| 2000 | -13.4 C (7.9 F) |
| 2001 | -14.7 C (5.5 F) |
| 2002 | -16.5 C (2.3 F) |
| 2003 | -16.2 C (2.8 F) |
| 2004 | -16.2 C (2.8 F) |
| 2005 | -12.5 C (9.5 F) |
| 2006 | -14.5 C (5.9 F) |
| 2007 | -17.2 C (1.0 F) |
| 2008 | -17.1 C (1.2 F) |
| 2009 | -11.7 C (10.9 F) |
| 2010 | -17.6 C (0.3 F) |
| 2011 | -21.6 C (-6.9 F) |
| 2012 | -11.3 C (11.7 F) |
| 2013 | -17.9 C (-0.2 F) |
| 2014 | -12.5 C (9.5 F) |
| 2015 | -13.8 C (7.2 F) |
| 2016 | -13.8 C (7.2 F) |
| 2017 | -13.1 C (8.4 F) |
| 2018 | -11.1 C (12.0 F) |
| 2019 | -14.4 C (6.1 F) |
| 2020 | -15.0 C (5.0 F) |
| 2021 | -11.3 C (11.7 F) |
| 2022 | -13.7 C (7.3 F) |
| 2023 | -14.2 C (6.4 F) |
| 2024 | -13.3 C (8.1 F) |
| 2025 | -15.6 C (3.9 F) |
| 2026 | -11.0 C (12.2 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1980 | 17.8 mm (0.7 in) |
| 1981 | 43.2 mm (1.7 in) |
| 1983 | 50.8 mm (2.0 in) |
| 1984 | 61.0 mm (2.4 in) |
| 1985 | 71.1 mm (2.8 in) |
| 1986 | 50.8 mm (2.0 in) |
| 1987 | 63.5 mm (2.5 in) |
| 1988 | 73.7 mm (2.9 in) |
| 1989 | 43.2 mm (1.7 in) |
| 1990 | 68.6 mm (2.7 in) |
| 1991 | 124.5 mm (4.9 in) |
| 1992 | 139.7 mm (5.5 in) |
| 1993 | 111.8 mm (4.4 in) |
| 1994 | 66.0 mm (2.6 in) |
| 1995 | 101.6 mm (4.0 in) |
| 1996 | 61.0 mm (2.4 in) |
| 1997 | 111.8 mm (4.4 in) |
| 1998 | 50.8 mm (2.0 in) |
| 1999 | 66.0 mm (2.6 in) |
| 2000 | 58.4 mm (2.3 in) |
| 2001 | 40.6 mm (1.6 in) |
| 2002 | 50.8 mm (2.0 in) |
| 2003 | 73.7 mm (2.9 in) |
| 2004 | 83.8 mm (3.3 in) |
| 2005 | 71.1 mm (2.8 in) |
| 2006 | 81.3 mm (3.2 in) |
| 2007 | 76.2 mm (3.0 in) |
| 2008 | 88.9 mm (3.5 in) |
| 2009 | 104.1 mm (4.1 in) |
| 2010 | 142.2 mm (5.6 in) |
| 2011 | 55.9 mm (2.2 in) |
| 2012 | 55.9 mm (2.2 in) |
| 2013 | 88.9 mm (3.5 in) |
| 2014 | 78.7 mm (3.1 in) |
| 2015 | 55.9 mm (2.2 in) |
| 2016 | 78.7 mm (3.1 in) |
| 2017 | 63.5 mm (2.5 in) |
| 2018 | 58.4 mm (2.3 in) |
| 2019 | 86.4 mm (3.4 in) |
| 2020 | 55.9 mm (2.2 in) |
| 2021 | 76.2 mm (3.0 in) |
| 2022 | 48.3 mm (1.9 in) |
| 2023 | 91.4 mm (3.6 in) |
| 2024 | 63.5 mm (2.5 in) |
| 2025 | 48.3 mm (1.9 in) |
| 2026 | 81.3 mm (3.2 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1980 | 40.7 mm (1.6 in) |
| 1981 | 101.6 mm (4.0 in) |
| 1983 | 111.8 mm (4.4 in) |
| 1984 | 127.0 mm (5.0 in) |
| 1985 | 111.7 mm (4.4 in) |
| 1986 | 106.7 mm (4.2 in) |
| 1987 | 149.9 mm (5.9 in) |
| 1988 | 139.7 mm (5.5 in) |
| 1989 | 81.3 mm (3.2 in) |
| 1990 | 119.4 mm (4.7 in) |
| 1991 | 241.4 mm (9.5 in) |
| 1992 | 144.8 mm (5.7 in) |
| 1993 | 289.6 mm (11.4 in) |
| 1994 | 129.5 mm (5.1 in) |
| 1995 | 160.0 mm (6.3 in) |
| 1996 | 111.8 mm (4.4 in) |
| 1997 | 142.3 mm (5.6 in) |
| 1998 | 111.9 mm (4.4 in) |
| 1999 | 139.7 mm (5.5 in) |
| 2000 | 124.4 mm (4.9 in) |
| 2001 | 68.6 mm (2.7 in) |
| 2002 | 76.1 mm (3.0 in) |
| 2003 | 228.7 mm (9.0 in) |
| 2004 | 99.0 mm (3.9 in) |
| 2005 | 187.9 mm (7.4 in) |
| 2006 | 116.8 mm (4.6 in) |
| 2007 | 175.2 mm (6.9 in) |
| 2008 | 182.8 mm (7.2 in) |
| 2009 | 134.5 mm (5.3 in) |
| 2010 | 320.0 mm (12.6 in) |
| 2011 | 116.8 mm (4.6 in) |
| 2012 | 132.0 mm (5.2 in) |
| 2013 | 162.6 mm (6.4 in) |
| 2014 | 109.2 mm (4.3 in) |
| 2015 | 96.5 mm (3.8 in) |
| 2016 | 172.7 mm (6.8 in) |
| 2017 | 172.8 mm (6.8 in) |
| 2018 | 83.8 mm (3.3 in) |
| 2019 | 175.3 mm (6.9 in) |
| 2020 | 116.8 mm (4.6 in) |
| 2021 | 160.0 mm (6.3 in) |
| 2022 | 61.0 mm (2.4 in) |
| 2023 | 132.0 mm (5.2 in) |
| 2024 | 109.2 mm (4.3 in) |
| 2025 | 127.1 mm (5.0 in) |
| 2026 | 149.8 mm (5.9 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1980 | 39 days |
| 1981 | 14 days |
| 1983 | 18 days |
| 1984 | 41 days |
| 1985 | 37 days |
| 1986 | 46 days |
| 1987 | 34 days |
| 1988 | 50 days |
| 1989 | 56 days |
| 1990 | 33 days |
| 1991 | 71 days |
| 1992 | 40 days |
| 1993 | 78 days |
| 1994 | 24 days |
| 1995 | 42 days |
| 1996 | 63 days |
| 1997 | 37 days |
| 1998 | 44 days |
| 1999 | 89 days |
| 2000 | 49 days |
| 2001 | 25 days |
| 2002 | 34 days |
| 2003 | 25 days |
| 2004 | 72 days |
| 2005 | 79 days |
| 2006 | 42 days |
| 2007 | 40 days |
| 2008 | 54 days |
| 2009 | 32 days |
| 2010 | 40 days |
| 2011 | 46 days |
| 2012 | 71 days |
| 2013 | 55 days |
| 2014 | 62 days |
| 2015 | 37 days |
| 2016 | 38 days |
| 2017 | 107 days |
| 2018 | 86 days |
| 2019 | 63 days |
| 2020 | 100 days |
| 2021 | 33 days |
| 2022 | 85 days |
| 2023 | 65 days |
| 2024 | 52 days |
| 2025 | 30 days |
| 2026 | 43 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
30 years with a frostAcross 30 years with a frost, the median last spring frost at Promontory falls on 12 May and the median first autumn frost on 16 October, which leaves a median of 159 days between them.
Fitted over all years, the growing season changes by +10.2 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1984 to 2025) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 12 May | n/a | 12 May | n/a | -2.3 days per decade |
| First autumn frost | 16 October | n/a | 16 October | n/a | +7.9 days per decade |
| Growing days | 159 days | n/a | 159 days | n/a | +10.2 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
42 years, 1984 to 2025A day with at least 69.2 mm (2.7 in) of rain is expected about once in 2 years. A day with at least 166.3 mm (6.5 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 69.2 mm (2.7 in) | |
| 5 years | 90.9 mm (3.6 in) | |
| 10 years | 106.8 mm (4.2 in) | |
| 25 years | 128.9 mm (5.1 in) | |
| 50 years | 147.0 mm (5.8 in) | Longer than the 42 years of record |
| 100 years | 166.3 mm (6.5 in) | Longer than the 42 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, 42 years of values from 1984 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: 142.2 mm (5.6 in) in 2010; 139.7 mm (5.5 in) in 1992; 124.5 mm (4.9 in) in 1991.
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 2026-10-17 (17 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-17).