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Built 2026-10-18 (18 October 2026)

Parley's Summit Weather Records (USS0011J52S)

Record envelope, standing records and threshold days for Parley's Summit (USS0011J52S), Utah, United States, with 49 years of record.

Key Facts for Parley's Summit

  • Parley's Summit (USS0011J52S) is a weather station in Utah, United States at 40.76 latitude and -111.63 longitude, 2,286 m (7,500 ft) above sea level.
  • The station reports from 1978 to 2026, 49 years of record.
  • 1,464 records set at Parley's Summit still stand.
  • Records are tracked for prcp: an element needs 30 years of data to be eligible.
  • Parley's Summit set a daily record precipitation of 27.9 mm (1.1 in) on 12 October 2026 (provisional).

Provisional Records

Records set in the last 60 days are provisional until they clear the revision window.

About the Station

  • Location: Utah, United States, 40.76 latitude, -111.63 longitude.
  • Elevation: 2,286 m (7,500 ft).
  • Period of record: 1978 to 2026, 49 years.
  • Eligible elements: prcp.

Daily Record Envelope and 2026

32 days at or beyond a record
Daily record high and record low at Parley's Summit, with 2026 drawn through them The band shows the record high and record low for each calendar day at Parley's Summit. The lines show the 2026 daily maximum and minimum. 32 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -40-2002040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Parley's Summit. The lines show the 2026 daily maximum and minimum. 32 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Parley's Summit, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan18.4 C (65.1 F)-23.9 C (-11.0 F)8.7 C (47.7 F)-13.7 C (7.3 F)
Feb14.4 C (57.9 F)-26.9 C (-16.4 F)10.6 C (51.1 F)-14.1 C (6.6 F)
Mar22.3 C (72.1 F)-18.0 C (-0.4 F)22.3 C (72.1 F)-9.6 C (14.7 F)
Apr24.2 C (75.6 F)-13.9 C (7.0 F)19.8 C (67.6 F)-10.6 C (12.9 F)
May28.2 C (82.8 F)-8.4 C (16.9 F)26.0 C (78.8 F)-3.5 C (25.7 F)
Jun31.4 C (88.5 F)-6.1 C (21.0 F)27.1 C (80.8 F)-0.7 C (30.7 F)
Jul33.6 C (92.5 F)2.1 C (35.8 F)33.6 C (92.5 F)9.7 C (49.5 F)
Aug32.5 C (90.5 F)0.6 C (33.1 F)32.5 C (90.5 F)8.6 C (47.5 F)
Sep31.7 C (89.1 F)-4.8 C (23.4 F)25.9 C (78.6 F)3.5 C (38.3 F)
Oct25.9 C (78.6 F)-20.4 C (-4.7 F)24.2 C (75.6 F)-0.2 C (31.6 F)
Nov19.2 C (66.6 F)-20.4 C (-4.7 F)n/an/a
Dec13.9 C (57.0 F)-25.2 C (-13.4 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Parley's Summit by the year they were set 1,464 records at Parley's Summit still stand. 2007 holds the most, with 112. 0501001502003: 592004: 422005: 442006: 702007: 1122008: 662009: 582010: 552011: 442012: 532013: 692014: 592015: 902016: 462017: 672018: 372019: 352020: 672021: 642022: 832023: 492024: 582025: 732026: 6420032006200920122015201820212024
1,464 records at Parley's Summit still stand. 2007 holds the most, with 112.
Standing records at Parley's Summit by the year they were set
Year setStanding records
200359
200442
200544
200670
2007112
200866
200958
201055
201144
201253
201369
201459
201590
201646
201767
201837
201935
202067
202164
202283
202349
202458
202573
202664

Wettest Day of Each Month

Oct: 58.4 mm (2.3 in)
Record daily precipitation for each month at Parley's Summit The wettest day on record for each calendar month at Parley's Summit. The most was 58.4 mm (2.3 in) on 11 October 1984. 0204060 Jan: 50.8 mm (2.0 in), 21 January 2012 Jan Feb: 50.8 mm (2.0 in), 7 February 2011 Feb Mar: 38.1 mm (1.5 in), 25 March 2009 Mar Apr: 43.2 mm (1.7 in), 25 April 1991 Apr May: 38.1 mm (1.5 in), 6 May 2024 May Jun: 48.3 mm (1.9 in), 6 June 2007 Jun Jul: 55.9 mm (2.2 in), 13 July 1983 Jul Aug: 45.7 mm (1.8 in), 20 August 1986 Aug Sep: 50.8 mm (2.0 in), 27 September 2014 Sep Oct: 58.4 mm (2.3 in), 11 October 1984 Oct Nov: 50.8 mm (2.0 in), 26 November 1989 Nov Dec: 55.9 mm (2.2 in), 29 December 2010 Dec
The wettest day on record for each calendar month at Parley's Summit. The most was 58.4 mm (2.3 in) on 11 October 1984.
Record daily precipitation for each month at Parley's Summit
MonthRecord daily precipitation (mm)Date
Jan50.8 mm (2.0 in)21 January 2012
Feb50.8 mm (2.0 in)7 February 2011
Mar38.1 mm (1.5 in)25 March 2009
Apr43.2 mm (1.7 in)25 April 1991
May38.1 mm (1.5 in)6 May 2024
Jun48.3 mm (1.9 in)6 June 2007
Jul55.9 mm (2.2 in)13 July 1983
Aug45.7 mm (1.8 in)20 August 1986
Sep50.8 mm (2.0 in)27 September 2014
Oct58.4 mm (2.3 in)11 October 1984
Nov50.8 mm (2.0 in)26 November 1989
Dec55.9 mm (2.2 in)29 December 2010

Period of Record Coverage

2003 to 2026
Days with data per year at Parley's Summit 24 years of record at Parley's Summit, 2003 to 2026. 3 years have data for under 90 percent of days and are left out of rankings: 2003, 2004, 2026. 2003: 223 of 365 days2004: 311 of 366 days2005: 365 of 365 days2006: 365 of 365 days2007: 361 of 365 days2008: 366 of 366 days2009: 365 of 365 days2010: 365 of 365 days2011: 365 of 365 days2012: 365 of 366 days2013: 365 of 365 days2014: 364 of 365 days2015: 365 of 365 days2016: 366 of 366 days2017: 365 of 365 days2018: 365 of 365 days2019: 365 of 365 days2020: 354 of 366 days2021: 365 of 365 days2022: 365 of 365 days2023: 365 of 365 days2024: 366 of 366 days2025: 365 of 365 days2026: 287 of 365 days20052010201520202025
24 years of record at Parley's Summit, 2003 to 2026. 3 years have data for under 90 percent of days and are left out of rankings: 2003, 2004, 2026.
Days with data per year at Parley's Summit
YearDays with dataShare of yearComplete
200322361%No
200431185%No
2005365100%Yes
2006365100%Yes
200736199%Yes
2008366100%Yes
2009365100%Yes
2010365100%Yes
2011365100%Yes
2012365100%Yes
2013365100%Yes
2014364100%Yes
2015365100%Yes
2016366100%Yes
2017365100%Yes
2018365100%Yes
2019365100%Yes
202035497%Yes
2021365100%Yes
2022365100%Yes
2023365100%Yes
2024366100%Yes
2025365100%Yes
202628779%No

Latest Records

20
Latest records at Parley's Summit
DateStationRecordValueBeat old record byOld record stoodSignificance
12 October 2026Parley's Summit, USdaily rain (Provisional)27.9 mm (1.1 in)12.7 mm (0.5 in)13 years23 of 100 (Routine)
18 September 2026Parley's Summit, USdaily rain (Tie, Provisional)22.9 mm (0.9 in)tie36 years3 of 100 (Routine)
29 August 2026Parley's Summit, USdaily rain (Provisional)20.3 mm (0.8 in)10.1 mm (0.4 in)32 years20 of 100 (Routine)
25 June 2026Parley's Summit, USdaily rain (Tie)7.6 mm (0.30 in)tie40 years4 of 100 (Routine)
2 April 2026Parley's Summit, USdaily rain (Tie)25.4 mm (1.0 in)tie47 years4 of 100 (Routine)
18 February 2026Parley's Summit, USdaily rain25.4 mm (1.0 in)5.1 mm (0.20 in)8 years13 of 100 (Routine)
4 October 2025Parley's Summit, USdaily rain40.6 mm (1.6 in)17.7 mm (0.7 in)30 years34 of 100 (Routine)
30 September 2025Parley's Summit, USdaily rain10.2 mm (0.4 in)2.6 mm (0.10 in)11 years10 of 100 (Routine)
27 August 2025Parley's Summit, USdaily rain (Tie)10.2 mm (0.4 in)tie11 years1 of 100 (Routine)
26 August 2025Parley's Summit, USdaily rain15.2 mm (0.6 in)5.0 mm (0.20 in)11 years14 of 100 (Routine)
5 May 2025Parley's Summit, USdaily rain (Tie)25.4 mm (1.0 in)tie44 years4 of 100 (Routine)
17 October 2024Parley's Summit, USdaily rain38.1 mm (1.5 in)10.2 mm (0.4 in)40 years28 of 100 (Routine)
17 August 2024Parley's Summit, USdaily rain15.2 mm (0.6 in)5.0 mm (0.20 in)19 years16 of 100 (Routine)
14 August 2024Parley's Summit, USdaily rain (Tie)12.7 mm (0.5 in)tie37 years3 of 100 (Routine)
13 August 2024Parley's Summit, USdaily rain12.7 mm (0.5 in)2.5 mm (0.10 in)40 years19 of 100 (Routine)
12 August 2024Parley's Summit, USdaily rain10.2 mm (0.4 in)2.6 mm (0.10 in)18 years12 of 100 (Routine)
27 June 2024Parley's Summit, USdaily rain5.1 mm (0.20 in)2.6 mm (0.10 in)28 years14 of 100 (Routine)
7 May 2024Parley's Summit, USdaily rain17.8 mm (0.7 in)2.6 mm (0.10 in)24 years14 of 100 (Routine)
6 May 2024Parley's Summit, USmonthly rain38.1 mm (1.5 in)2.5 mm (0.10 in)40 years29 of 100 (Routine)
12 March 2024Parley's Summit, USdaily rain15.2 mm (0.6 in)5.0 mm (0.20 in)5 years12 of 100 (Routine)

Climate Trend

21 complete years, 2005 to 2025
Annual mean temperature at Parley's Summit as warming stripes, 2005 to 2025 One stripe for each of 21 complete years at Parley's Summit, 2005 to 2025. Blue stripes are years cooler than the station's own mean of 6.1 C (42.9 F); red stripes are warmer. The coolest year was 2007, at 3.6 C (38.5 F), and the warmest was 2025, at 7.5 C (45.5 F). The strongest colour marks a difference of 2.5 C (4.5 F). 2005: 6.3 C, +0.2 C from the station mean2006: 4.6 C, -1.5 C from the station mean2007: 3.6 C, -2.4 C from the station mean2008: 5.2 C, -0.9 C from the station mean2009: 5.4 C, -0.6 C from the station mean2010: 5.5 C, -0.6 C from the station mean2011: 5.0 C, -1.1 C from the station mean2012: 7.2 C, +1.1 C from the station mean2013: 5.7 C, -0.4 C from the station mean2014: 6.5 C, +0.4 C from the station mean2015: 7.1 C, +1.0 C from the station mean2016: 6.8 C, +0.8 C from the station mean2017: 6.7 C, +0.6 C from the station mean2018: 6.6 C, +0.6 C from the station mean2019: 5.2 C, -0.9 C from the station mean2020: 6.6 C, +0.6 C from the station mean2021: 6.8 C, +0.8 C from the station mean2022: 6.0 C, -0.1 C from the station mean2023: 5.7 C, -0.3 C from the station mean2024: 7.0 C, +1.0 C from the station mean2025: 7.5 C, +1.4 C from the station mean2005200820102012201420162018202020222024
One stripe for each of 21 complete years at Parley's Summit, 2005 to 2025. Blue stripes are years cooler than the station's own mean of 6.1 C (42.9 F); red stripes are warmer. The coolest year was 2007, at 3.6 C (38.5 F), and the warmest was 2025, at 7.5 C (45.5 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Parley's Summit as warming stripes, 2005 to 2025
YearAnnual mean temperatureDifference from the station mean
20056.3 C+0.25 C
20064.6 C-1.45 C
20073.6 C-2.42 C
20085.2 C-0.85 C
20095.4 C-0.62 C
20105.5 C-0.55 C
20115.0 C-1.05 C
20127.2 C+1.11 C
20135.7 C-0.40 C
20146.5 C+0.45 C
20157.1 C+1.02 C
20166.8 C+0.78 C
20176.7 C+0.64 C
20186.6 C+0.58 C
20195.2 C-0.86 C
20206.6 C+0.56 C
20216.8 C+0.76 C
20226.0 C-0.05 C
20235.7 C-0.31 C
20247.0 C+0.99 C
20257.5 C+1.44 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

1978 to 2026
Yearly extremes at Parley's Summit: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)33.6 C (92.5 F)202631.1 C (87.9 F)24
Coldest night (TNn)-26.9 C (-16.4 F)2011-20.5 C (-4.9 F)24
Wettest day (Rx1day)58.4 mm (2.3 in)198440.6 mm (1.6 in)49
Wettest five days (Rx5day)119.4 mm (4.7 in)198273.7 mm (2.9 in)49
Longest dry spell (CDD)62 days198829 days49

Hottest day (TXx)

Hottest day (TXx) at Parley's Summit by year The hottest day of the year at Parley's Summit, 1978 to 2026. The record is 33.6 C (92.5 F) in 2026, marked on the chart; the median year is 31.1 C (87.9 F). 2830323419801990200020102020Record: 33.6 C (92.5 F) in 2026
The hottest day of the year at Parley's Summit, 1978 to 2026. The record is 33.6 C (92.5 F) in 2026, marked on the chart; the median year is 31.1 C (87.9 F).
Hottest day (TXx) at Parley's Summit by year
YearHottest day (TXx)
1978n/a
1979n/a
1980n/a
1981n/a
1982n/a
1983n/a
1984n/a
1985n/a
1986n/a
1987n/a
1988n/a
1989n/a
1990n/a
1991n/a
1992n/a
1993n/a
1994n/a
1995n/a
1996n/a
1997n/a
1998n/a
1999n/a
2000n/a
2001n/a
2002n/a
200332.3 C (90.1 F)
200428.7 C (83.7 F)
200531.1 C (88.0 F)
200631.2 C (88.2 F)
200731.5 C (88.7 F)
200829.8 C (85.6 F)
200930.0 C (86.0 F)
201029.2 C (84.6 F)
201129.0 C (84.2 F)
201231.1 C (88.0 F)
201331.4 C (88.5 F)
201430.9 C (87.6 F)
201530.9 C (87.6 F)
201631.0 C (87.8 F)
201730.4 C (86.7 F)
201831.1 C (88.0 F)
201929.8 C (85.6 F)
202032.1 C (89.8 F)
202132.2 C (90.0 F)
202231.7 C (89.1 F)
202330.4 C (86.7 F)
202432.3 C (90.1 F)
202530.8 C (87.4 F)
202633.6 C (92.5 F)

Coldest night (TNn)

Coldest night (TNn) at Parley's Summit by year The coldest night of the year at Parley's Summit, 1978 to 2026. The record is -26.9 C (-16.4 F) in 2011, marked on the chart; the median year is -20.5 C (-4.9 F). -30-25-20-15-1019801990200020102020Record: -26.9 C (-16.4 F) in 2011
The coldest night of the year at Parley's Summit, 1978 to 2026. The record is -26.9 C (-16.4 F) in 2011, marked on the chart; the median year is -20.5 C (-4.9 F).
Coldest night (TNn) at Parley's Summit by year
YearColdest night (TNn)
1978n/a
1979n/a
1980n/a
1981n/a
1982n/a
1983n/a
1984n/a
1985n/a
1986n/a
1987n/a
1988n/a
1989n/a
1990n/a
1991n/a
1992n/a
1993n/a
1994n/a
1995n/a
1996n/a
1997n/a
1998n/a
1999n/a
2000n/a
2001n/a
2002n/a
2003-18.7 C (-1.7 F)
2004-18.8 C (-1.8 F)
2005-20.4 C (-4.7 F)
2006-20.7 C (-5.3 F)
2007-22.9 C (-9.2 F)
2008-20.2 C (-4.4 F)
2009-21.2 C (-6.2 F)
2010-20.6 C (-5.1 F)
2011-26.9 C (-16.4 F)
2012-17.8 C (0.0 F)
2013-23.9 C (-11.0 F)
2014-25.2 C (-13.4 F)
2015-20.4 C (-4.7 F)
2016-22.4 C (-8.3 F)
2017-23.9 C (-11.0 F)
2018-19.8 C (-3.6 F)
2019-21.0 C (-5.8 F)
2020-20.2 C (-4.4 F)
2021-18.4 C (-1.1 F)
2022-21.7 C (-7.1 F)
2023-21.7 C (-7.1 F)
2024-14.8 C (5.4 F)
2025-19.6 C (-3.3 F)
2026-14.1 C (6.6 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Parley's Summit by year The wettest day of the year at Parley's Summit, 1978 to 2026. The record is 58.4 mm (2.3 in) in 1984, marked on the chart; the median year is 40.6 mm (1.6 in). 203040506019801990200020102020Record: 58.4 mm (2.3 in) in 1984
The wettest day of the year at Parley's Summit, 1978 to 2026. The record is 58.4 mm (2.3 in) in 1984, marked on the chart; the median year is 40.6 mm (1.6 in).
Wettest day (Rx1day) at Parley's Summit by year
YearWettest day (Rx1day)
197827.9 mm (1.1 in)
197943.2 mm (1.7 in)
198040.6 mm (1.6 in)
198143.2 mm (1.7 in)
198243.2 mm (1.7 in)
198355.9 mm (2.2 in)
198458.4 mm (2.3 in)
198530.5 mm (1.2 in)
198645.7 mm (1.8 in)
198730.5 mm (1.2 in)
198845.7 mm (1.8 in)
198950.8 mm (2.0 in)
199025.4 mm (1.0 in)
199143.2 mm (1.7 in)
199238.1 mm (1.5 in)
199340.6 mm (1.6 in)
199430.5 mm (1.2 in)
199543.2 mm (1.7 in)
199635.6 mm (1.4 in)
199738.1 mm (1.5 in)
199833.0 mm (1.3 in)
199935.6 mm (1.4 in)
200030.5 mm (1.2 in)
200140.6 mm (1.6 in)
200233.0 mm (1.3 in)
200335.6 mm (1.4 in)
200448.3 mm (1.9 in)
200530.5 mm (1.2 in)
200635.6 mm (1.4 in)
200748.3 mm (1.9 in)
200845.7 mm (1.8 in)
200938.1 mm (1.5 in)
201055.9 mm (2.2 in)
201150.8 mm (2.0 in)
201250.8 mm (2.0 in)
201327.9 mm (1.1 in)
201450.8 mm (2.0 in)
201535.6 mm (1.4 in)
201638.1 mm (1.5 in)
201745.7 mm (1.8 in)
201830.5 mm (1.2 in)
201940.6 mm (1.6 in)
202035.6 mm (1.4 in)
202143.2 mm (1.7 in)
202250.8 mm (2.0 in)
202348.3 mm (1.9 in)
202438.1 mm (1.5 in)
202540.6 mm (1.6 in)
202627.9 mm (1.1 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Parley's Summit by year The wettest five days of the year at Parley's Summit, 1978 to 2026. The record is 119.4 mm (4.7 in) in 1982, marked on the chart; the median year is 73.7 mm (2.9 in). 25507510012519801990200020102020Record: 119.4 mm (4.7 in) in 1982
The wettest five days of the year at Parley's Summit, 1978 to 2026. The record is 119.4 mm (4.7 in) in 1982, marked on the chart; the median year is 73.7 mm (2.9 in).
Wettest five days (Rx5day) at Parley's Summit by year
YearWettest five days (Rx5day)
197850.7 mm (2.0 in)
197983.8 mm (3.3 in)
198083.7 mm (3.3 in)
198176.2 mm (3.0 in)
1982119.4 mm (4.7 in)
198371.1 mm (2.8 in)
1984116.7 mm (4.6 in)
198573.7 mm (2.9 in)
198671.1 mm (2.8 in)
198763.5 mm (2.5 in)
198876.2 mm (3.0 in)
198978.7 mm (3.1 in)
199035.6 mm (1.4 in)
1991111.8 mm (4.4 in)
199281.3 mm (3.2 in)
1993101.6 mm (4.0 in)
199466.0 mm (2.6 in)
199566.0 mm (2.6 in)
199691.4 mm (3.6 in)
199750.8 mm (2.0 in)
199871.1 mm (2.8 in)
199981.3 mm (3.2 in)
200063.5 mm (2.5 in)
2001111.7 mm (4.4 in)
200263.5 mm (2.5 in)
200373.7 mm (2.9 in)
200491.4 mm (3.6 in)
200573.7 mm (2.9 in)
200678.7 mm (3.1 in)
200758.3 mm (2.3 in)
200868.5 mm (2.7 in)
200981.3 mm (3.2 in)
2010114.4 mm (4.5 in)
201161.0 mm (2.4 in)
201283.8 mm (3.3 in)
201345.7 mm (1.8 in)
201486.4 mm (3.4 in)
201571.1 mm (2.8 in)
201668.5 mm (2.7 in)
201771.2 mm (2.8 in)
201863.5 mm (2.5 in)
201983.7 mm (3.3 in)
202083.8 mm (3.3 in)
202199.1 mm (3.9 in)
202273.7 mm (2.9 in)
202394.0 mm (3.7 in)
202481.3 mm (3.2 in)
202571.2 mm (2.8 in)
202673.6 mm (2.9 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Parley's Summit by year The longest dry spell of the year at Parley's Summit, 1978 to 2026. The record is 62 days in 1988, marked on the chart; the median year is 29 days. 02040608019801990200020102020Record: 62 days in 1988
The longest dry spell of the year at Parley's Summit, 1978 to 2026. The record is 62 days in 1988, marked on the chart; the median year is 29 days.
Longest dry spell (CDD) at Parley's Summit by year
YearLongest dry spell (CDD)
197814 days
197942 days
198049 days
198126 days
198224 days
198321 days
198441 days
198537 days
198622 days
198732 days
198862 days
198924 days
199027 days
199149 days
199223 days
199318 days
199434 days
199518 days
199629 days
199726 days
199819 days
199930 days
200017 days
200123 days
200252 days
200329 days
200418 days
200545 days
200625 days
200747 days
200860 days
200923 days
201039 days
201120 days
201238 days
201335 days
201431 days
201528 days
201652 days
201740 days
201841 days
201943 days
202026 days
202131 days
202218 days
202315 days
202432 days
202533 days
202625 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

21 years with a frost

Across 21 years with a frost, the median last spring frost at Parley's Summit falls on 10 June and the median first autumn frost on 3 October, which leaves a median of 121 days between them.

Frost dates and growing season at Parley's Summit
MeasureMedian, all yearsEarliest periodRecent period (2005 to 2025)Recent against earliestFitted trend
Last spring frost10 Junen/a10 Junen/an/a
First autumn frost3 Octobern/a3 Octobern/an/a
Growing days121 daysn/a121 daysn/an/a

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

47 years, 1979 to 2025

A day with at least 40.5 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 60.7 mm (2.4 in) of rain is expected about once in 100 years.

Rainfall return levels at Parley's Summit: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years40.5 mm (1.6 in)
5 years47.7 mm (1.9 in)
10 years51.7 mm (2.0 in)
25 years55.8 mm (2.2 in)
50 years58.5 mm (2.3 in)Longer than the 47 years of record
100 years60.7 mm (2.4 in)Longer than the 47 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, 47 years of values from 1979 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: 58.4 mm (2.3 in) in 1984; 55.9 mm (2.2 in) in 1983; 55.9 mm (2.2 in) in 2010.

Download the Data

  • Data for Parley's Summit standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Parley's Summit threshold days by year: CSV or JSON. Field meanings are on the data page.

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).