Built 2026-10-19 (19 October 2026)

South Pass Weather Records (USS0008G03S)

Record envelope, standing records and threshold days for South Pass (USS0008G03S), Wyoming, United States, with 42 years of record.

Key Facts for South Pass

  • South Pass (USS0008G03S) is a weather station in Wyoming, United States at 42.57 latitude and -108.84 longitude, 2,755 m (9,040 ft) above sea level.
  • The station reports from 1985 to 2026, 42 years of record.
  • 1,464 records set at South Pass still stand.
  • Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
  • South Pass set a daily record precipitation of 25.4 mm (1.0 in) on 11 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, 42.57 latitude, -108.84 longitude.
  • Elevation: 2,755 m (9,040 ft).
  • Period of record: 1985 to 2026, 42 years.
  • Eligible elements: tmax, tmin, prcp.

Daily Record Envelope and 2026

11 days at or beyond a record
Daily record high and record low at South Pass, with 2026 drawn through them The band shows the record high and record low for each calendar day at South Pass. The lines show the 2026 daily maximum and minimum. 11 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 South Pass. The lines show the 2026 daily maximum and minimum. 11 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at South Pass, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan15.8 C (60.4 F)-30.9 C (-23.6 F)9.3 C (48.7 F)-22.6 C (-8.7 F)
Feb16.5 C (61.7 F)-32.4 C (-26.3 F)9.4 C (48.9 F)-22.6 C (-8.7 F)
Mar18.6 C (65.5 F)-29.1 C (-20.4 F)16.4 C (61.5 F)-19.9 C (-3.8 F)
Apr21.6 C (70.9 F)-23.5 C (-10.3 F)16.6 C (61.9 F)-14.0 C (6.8 F)
May25.7 C (78.3 F)-16.2 C (2.8 F)22.9 C (73.2 F)-13.6 C (7.5 F)
Jun30.4 C (86.7 F)-7.0 C (19.4 F)24.6 C (76.3 F)-3.6 C (25.5 F)
Jul31.9 C (89.4 F)-3.3 C (26.1 F)31.0 C (87.8 F)2.3 C (36.1 F)
Aug30.2 C (86.4 F)-3.4 C (25.9 F)29.5 C (85.1 F)1.6 C (34.9 F)
Sep28.7 C (83.7 F)-15.4 C (4.3 F)21.4 C (70.5 F)-2.4 C (27.7 F)
Oct23.1 C (73.6 F)-23.8 C (-10.8 F)20.9 C (69.6 F)0.0 C (32.0 F)
Nov16.5 C (61.7 F)-30.4 C (-22.7 F)n/an/a
Dec14.0 C (57.2 F)-38.6 C (-37.5 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at South Pass by the year they were set 1,464 records at South Pass still stand. 1996 holds the most, with 57. 02040601985: 171986: 341987: 461988: 491989: 461990: 441991: 361992: 421993: 291994: 331995: 311996: 571997: 321998: 321999: 492000: 382001: 252002: 362003: 482004: 252005: 302006: 482007: 282008: 282009: 402010: 292011: 242012: 442013: 472014: 352015: 312016: 242017: 262018: 182019: 222020: 382021: 462022: 382023: 252024: 182025: 402026: 36198519901995200020052010201520202025
1,464 records at South Pass still stand. 1996 holds the most, with 57.
Standing records at South Pass by the year they were set
Year setStanding records
198517
198634
198746
198849
198946
199044
199136
199242
199329
199433
199531
199657
199732
199832
199949
200038
200125
200236
200348
200425
200530
200648
200728
200828
200940
201029
201124
201244
201347
201435
201531
201624
201726
201818
201922
202038
202146
202238
202325
202418
202540
202636

All-Time Record Progression

2 new records
When South Pass set new all-time records 2 all-time records were set at South Pass between 15 July 2026 and 25 July 2026. Each dot is a new record. Record high minimum temperature15 July 2026: Record high minimum temperature 14.6 C (58.3 F)25 July 2026: Record high minimum temperature 15.2 C (59.4 F)
2 all-time records were set at South Pass between 15 July 2026 and 25 July 2026. Each dot is a new record.
When South Pass set new all-time records
DateKindDetail
2026-07-15Record high minimum temperatureRecord high minimum temperature 14.6 C (58.3 F)
2026-07-25Record high minimum temperatureRecord high minimum temperature 15.2 C (59.4 F)

Wettest Day of Each Month

May: 99.1 mm (3.9 in)
Record daily precipitation for each month at South Pass The wettest day on record for each calendar month at South Pass. The most was 99.1 mm (3.9 in) on 19 May 2011. 0255075100 Jan: 61.0 mm (2.4 in), 9 January 2017 Jan Feb: 68.6 mm (2.7 in), 17 February 1986 Feb Mar: 50.8 mm (2.0 in), 31 March 2017 Mar Apr: 71.1 mm (2.8 in), 22 April 1999 Apr May: 99.1 mm (3.9 in), 19 May 2011 May Jun: 43.2 mm (1.7 in), 12 June 2010 Jun Jul: 33.0 mm (1.3 in), 10 July 1987 Jul Aug: 27.9 mm (1.1 in), 18 August 2004 Aug Sep: 38.1 mm (1.5 in), 20 September 1989 Sep Oct: 43.2 mm (1.7 in), 22 October 1995 Oct Nov: 58.4 mm (2.3 in), 24 November 1985 Nov Dec: 45.7 mm (1.8 in), 21 December 1996 Dec
The wettest day on record for each calendar month at South Pass. The most was 99.1 mm (3.9 in) on 19 May 2011.
Record daily precipitation for each month at South Pass
MonthRecord daily precipitation (mm)Date
Jan61.0 mm (2.4 in)9 January 2017
Feb68.6 mm (2.7 in)17 February 1986
Mar50.8 mm (2.0 in)31 March 2017
Apr71.1 mm (2.8 in)22 April 1999
May99.1 mm (3.9 in)19 May 2011
Jun43.2 mm (1.7 in)12 June 2010
Jul33.0 mm (1.3 in)10 July 1987
Aug27.9 mm (1.1 in)18 August 2004
Sep38.1 mm (1.5 in)20 September 1989
Oct43.2 mm (1.7 in)22 October 1995
Nov58.4 mm (2.3 in)24 November 1985
Dec45.7 mm (1.8 in)21 December 1996

Period of Record Coverage

1985 to 2026
Days with data per year at South Pass 42 years of record at South Pass, 1985 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1985, 2026. 1985: 109 of 365 days1986: 363 of 365 days1987: 362 of 365 days1988: 357 of 366 days1989: 356 of 365 days1990: 360 of 365 days1991: 362 of 365 days1992: 364 of 366 days1993: 346 of 365 days1994: 347 of 365 days1995: 364 of 365 days1996: 364 of 366 days1997: 365 of 365 days1998: 365 of 365 days1999: 365 of 365 days2000: 365 of 366 days2001: 365 of 365 days2002: 365 of 365 days2003: 365 of 365 days2004: 366 of 366 days2005: 365 of 365 days2006: 365 of 365 days2007: 365 of 365 days2008: 366 of 366 days2009: 365 of 365 days2010: 365 of 365 days2011: 365 of 365 days2012: 366 of 366 days2013: 365 of 365 days2014: 365 of 365 days2015: 365 of 365 days2016: 366 of 366 days2017: 365 of 365 days2018: 365 of 365 days2019: 365 of 365 days2020: 366 of 366 days2021: 365 of 365 days2022: 365 of 365 days2023: 365 of 365 days2024: 366 of 366 days2025: 364 of 365 days2026: 287 of 365 days1990200020102020
42 years of record at South Pass, 1985 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1985, 2026.
Days with data per year at South Pass
YearDays with dataShare of yearComplete
198510930%No
198636399%Yes
198736299%Yes
198835798%Yes
198935698%Yes
199036099%Yes
199136299%Yes
199236499%Yes
199334695%Yes
199434795%Yes
1995364100%Yes
199636499%Yes
1997365100%Yes
1998365100%Yes
1999365100%Yes
2000365100%Yes
2001365100%Yes
2002365100%Yes
2003365100%Yes
2004366100%Yes
2005365100%Yes
2006365100%Yes
2007365100%Yes
2008366100%Yes
2009365100%Yes
2010365100%Yes
2011365100%Yes
2012366100%Yes
2013365100%Yes
2014365100%Yes
2015365100%Yes
2016366100%Yes
2017365100%Yes
2018365100%Yes
2019365100%Yes
2020366100%Yes
2021365100%Yes
2022365100%Yes
2023365100%Yes
2024366100%Yes
2025364100%Yes
202628779%No

Latest Records

20
Latest records at South Pass
DateStationRecordValueBeat old record byOld record stoodSignificance
11 October 2026South Pass, USdaily rain (Provisional)25.4 mm (1.0 in)2.5 mm (0.10 in)17 years12 of 100 (Routine)
9 October 2026South Pass, USdaily high min (Provisional)5.1 C (41.2 F)1.2 C (2.2 F)21 years12 of 100 (Routine)
8 October 2026South Pass, USdaily high min (Provisional)3.6 C (38.5 F)1.0 C (1.8 F)7 years8 of 100 (Routine)
7 October 2026South Pass, USdaily high min (Tie, Provisional)2.6 C (36.7 F)tie12 years1 of 100 (Routine)
6 October 2026South Pass, USdaily high min (Provisional)5.1 C (41.2 F)1.6 C (2.9 F)20 years13 of 100 (Routine)
5 October 2026South Pass, USdaily high min (Provisional)6.8 C (44.2 F)2.8 C (5.0 F)19 years14 of 100 (Routine)
28 September 2026South Pass, USdaily rain (Provisional)15.2 mm (0.6 in)7.6 mm (0.30 in)27 years20 of 100 (Routine)
13 September 2026South Pass, USdaily high min (Tie, Provisional)7.5 C (45.5 F)tie8 years1 of 100 (Routine)
29 August 2026South Pass, USdaily rain (Provisional)15.2 mm (0.6 in)10.1 mm (0.4 in)23 years20 of 100 (Routine)
29 August 2026South Pass, USdaily low max (Provisional)12.5 C (54.5 F)1.1 C (2.0 F)23 years12 of 100 (Routine)
21 August 2026South Pass, USdaily high max (Provisional)29.5 C (85.1 F)2.8 C (5.0 F)16 years16 of 100 (Routine)
21 August 2026South Pass, USmonthly high min (Provisional)13.6 C (56.5 F)0.1 C (0.2 F)0 years14 of 100 (Routine)
11 August 2026South Pass, USmonthly high min13.5 C (56.3 F)0.2 C (0.4 F)25 years21 of 100 (Routine)
8 August 2026South Pass, USdaily high min13.1 C (55.6 F)1.1 C (2.0 F)25 years14 of 100 (Routine)
8 August 2026South Pass, USdaily high max28.0 C (82.4 F)0.4 C (0.7 F)25 years12 of 100 (Routine)
27 July 2026South Pass, USdaily rain (Tie)7.6 mm (0.30 in)tie20 years2 of 100 (Routine)
26 July 2026South Pass, USdaily high min14.1 C (57.4 F)3.3 C (5.9 F)37 years26 of 100 (Routine)
26 July 2026South Pass, USdaily high max (Tie)28.8 C (83.8 F)tie16 years2 of 100 (Routine)
25 July 2026South Pass, USall-time high min15.2 C (59.4 F)0.6 C (1.1 F)0 years26 of 100 (Routine)
22 July 2026South Pass, USdaily rain20.3 mm (0.8 in)15.2 mm (0.6 in)40 years20 of 100 (Routine)

Climate Trend

40 complete years, 1986 to 2025
Annual mean temperature at South Pass as warming stripes, 1986 to 2025 One stripe for each of 40 complete years at South Pass, 1986 to 2025. Blue stripes are years cooler than the station's own mean of 2.2 C (36.0 F); red stripes are warmer. The coolest year was 1998, at -0.4 C (31.3 F), and the warmest was 2012, at 3.6 C (38.6 F). The strongest colour marks a difference of 2.7 C (4.9 F). 1986: 2.1 C, -0.2 C from the station mean1987: 2.2 C, 0.0 C from the station mean1988: 2.7 C, +0.5 C from the station mean1989: 1.8 C, -0.4 C from the station mean1990: 1.7 C, -0.5 C from the station mean1991: 2.2 C, 0.0 C from the station mean1992: 2.9 C, +0.7 C from the station mean1993: 1.2 C, -1.0 C from the station mean1994: 2.7 C, +0.5 C from the station mean1995: 2.3 C, 0.0 C from the station mean1996: 2.0 C, -0.2 C from the station mean1997: 1.0 C, -1.3 C from the station mean1998: -0.4 C, -2.6 C from the station mean1999: 1.2 C, -1.1 C from the station mean2000: 1.9 C, -0.3 C from the station mean2001: 2.5 C, +0.3 C from the station mean2002: 1.2 C, -1.0 C from the station mean2003: 2.3 C, +0.1 C from the station mean2004: 2.0 C, -0.2 C from the station mean2005: 2.6 C, +0.4 C from the station mean2006: 2.8 C, +0.6 C from the station mean2007: 3.3 C, +1.1 C from the station mean2008: 1.6 C, -0.6 C from the station mean2009: 1.9 C, -0.3 C from the station mean2010: 2.3 C, +0.1 C from the station mean2011: 1.8 C, -0.4 C from the station mean2012: 3.6 C, +1.4 C from the station mean2013: 2.4 C, +0.2 C from the station mean2014: 2.5 C, +0.2 C from the station mean2015: 3.5 C, +1.3 C from the station mean2016: 3.0 C, +0.8 C from the station mean2017: 2.6 C, +0.4 C from the station mean2018: 2.2 C, 0.0 C from the station mean2019: 1.5 C, -0.7 C from the station mean2020: 2.4 C, +0.2 C from the station mean2021: 2.6 C, +0.4 C from the station mean2022: 2.0 C, -0.2 C from the station mean2023: 2.0 C, -0.2 C from the station mean2024: 3.1 C, +0.9 C from the station mean2025: 3.3 C, +1.1 C from the station mean198619901995200020052010201520202025
One stripe for each of 40 complete years at South Pass, 1986 to 2025. Blue stripes are years cooler than the station's own mean of 2.2 C (36.0 F); red stripes are warmer. The coolest year was 1998, at -0.4 C (31.3 F), and the warmest was 2012, at 3.6 C (38.6 F). The strongest colour marks a difference of 2.7 C (4.9 F).
Annual mean temperature at South Pass as warming stripes, 1986 to 2025
YearAnnual mean temperatureDifference from the station mean
19862.1 C-0.16 C
19872.2 C+0.03 C
19882.7 C+0.47 C
19891.8 C-0.38 C
19901.7 C-0.49 C
19912.2 C-0.01 C
19922.9 C+0.66 C
19931.2 C-1.03 C
19942.7 C+0.50 C
19952.3 C+0.04 C
19962.0 C-0.19 C
19971.0 C-1.26 C
1998-0.4 C-2.62 C
19991.2 C-1.06 C
20001.9 C-0.28 C
20012.5 C+0.28 C
20021.2 C-1.01 C
20032.3 C+0.10 C
20042.0 C-0.22 C
20052.6 C+0.41 C
20062.8 C+0.58 C
20073.3 C+1.08 C
20081.6 C-0.57 C
20091.9 C-0.35 C
20102.3 C+0.08 C
20111.8 C-0.38 C
20123.6 C+1.43 C
20132.4 C+0.20 C
20142.5 C+0.24 C
20153.5 C+1.31 C
20163.0 C+0.79 C
20172.6 C+0.35 C
20182.2 C-0.02 C
20191.5 C-0.69 C
20202.4 C+0.21 C
20212.6 C+0.42 C
20222.0 C-0.21 C
20232.0 C-0.22 C
20243.1 C+0.85 C
20253.3 C+1.06 C

The annual mean temperature here has risen by 0.21 C (0.01 to 0.42) per decade over 1986 to 2025. In Fahrenheit: 0.38 F (0.02 to 0.75) per decade. The slope is a straight line fitted to 40 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at South Pass
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.21 C (0.01 to 0.42) per decade0.38 F (0.02 to 0.75) per decade1986 to 202540Rise
Mean daily maximum-0.2 C (-0.5 to 0.1) per decade-0.3 F (-0.8 to 0.1) per decade1986 to 202540Not clearly different from zero
Mean daily minimum0.6 C (0.4 to 0.8) per decade1.1 F (0.8 to 1.4) per decade1986 to 202540Rise

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

1985 to 2026
Yearly extremes at South Pass: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)31.9 C (89.4 F)198929.3 C (84.7 F)42
Coldest night (TNn)-38.6 C (-37.5 F)1990-29.3 C (-20.7 F)42
Wettest day (Rx1day)99.1 mm (3.9 in)201136.9 mm (1.5 in)42
Wettest five days (Rx5day)213.4 mm (8.4 in)198663.5 mm (2.5 in)42
Longest dry spell (CDD)64 days201330 days42

Hottest day (TXx)

Hottest day (TXx) at South Pass by year The hottest day of the year at South Pass, 1985 to 2026. The record is 31.9 C (89.4 F) in 1989, marked on the chart; the median year is 29.3 C (84.7 F). 15202530351990200020102020Record: 31.9 C (89.4 F) in 1989
The hottest day of the year at South Pass, 1985 to 2026. The record is 31.9 C (89.4 F) in 1989, marked on the chart; the median year is 29.3 C (84.7 F).
Hottest day (TXx) at South Pass by year
YearHottest day (TXx)
198517.4 C (63.3 F)
198630.2 C (86.4 F)
198727.3 C (81.1 F)
198831.2 C (88.2 F)
198931.9 C (89.4 F)
199030.2 C (86.4 F)
199129.2 C (84.6 F)
199229.4 C (84.9 F)
199326.7 C (80.1 F)
199429.8 C (85.6 F)
199530.5 C (86.9 F)
199629.4 C (84.9 F)
199729.5 C (85.1 F)
199826.0 C (78.8 F)
199930.2 C (86.4 F)
200029.9 C (85.8 F)
200129.8 C (85.6 F)
200231.4 C (88.5 F)
200329.4 C (84.9 F)
200427.0 C (80.6 F)
200529.9 C (85.8 F)
200631.5 C (88.7 F)
200730.1 C (86.2 F)
200828.1 C (82.6 F)
200928.6 C (83.5 F)
201028.8 C (83.8 F)
201128.0 C (82.4 F)
201229.9 C (85.8 F)
201328.7 C (83.7 F)
201428.5 C (83.3 F)
201528.8 C (83.8 F)
201628.3 C (82.9 F)
201727.8 C (82.0 F)
201829.0 C (84.2 F)
201927.4 C (81.3 F)
202028.7 C (83.7 F)
202130.8 C (87.4 F)
202228.7 C (83.7 F)
202329.1 C (84.4 F)
202429.6 C (85.3 F)
202528.6 C (83.5 F)
202631.0 C (87.8 F)

Coldest night (TNn)

Coldest night (TNn) at South Pass by year The coldest night of the year at South Pass, 1985 to 2026. The record is -38.6 C (-37.5 F) in 1990, marked on the chart; the median year is -29.3 C (-20.7 F). -40-35-30-25-201990200020102020Record: -38.6 C (-37.5 F) in 1990
The coldest night of the year at South Pass, 1985 to 2026. The record is -38.6 C (-37.5 F) in 1990, marked on the chart; the median year is -29.3 C (-20.7 F).
Coldest night (TNn) at South Pass by year
YearColdest night (TNn)
1985-29.4 C (-20.9 F)
1986-29.4 C (-20.9 F)
1987-29.1 C (-20.4 F)
1988-26.6 C (-15.9 F)
1989-32.0 C (-25.6 F)
1990-38.6 C (-37.5 F)
1991-30.9 C (-23.6 F)
1992-27.2 C (-17.0 F)
1993-31.7 C (-25.1 F)
1994-26.7 C (-16.1 F)
1995-25.8 C (-14.4 F)
1996-31.3 C (-24.3 F)
1997-30.0 C (-22.0 F)
1998-36.5 C (-33.7 F)
1999-26.1 C (-15.0 F)
2000-24.1 C (-11.4 F)
2001-27.1 C (-16.8 F)
2002-30.0 C (-22.0 F)
2003-30.9 C (-23.6 F)
2004-29.6 C (-21.3 F)
2005-28.7 C (-19.7 F)
2006-29.0 C (-20.2 F)
2007-28.9 C (-20.0 F)
2008-27.4 C (-17.3 F)
2009-30.4 C (-22.7 F)
2010-29.3 C (-20.7 F)
2011-32.4 C (-26.3 F)
2012-23.7 C (-10.7 F)
2013-29.3 C (-20.7 F)
2014-31.3 C (-24.3 F)
2015-25.9 C (-14.6 F)
2016-29.8 C (-21.6 F)
2017-28.3 C (-18.9 F)
2018-25.7 C (-14.3 F)
2019-26.4 C (-15.5 F)
2020-23.0 C (-9.4 F)
2021-26.4 C (-15.5 F)
2022-33.6 C (-28.5 F)
2023-30.3 C (-22.5 F)
2024-29.8 C (-21.6 F)
2025-30.2 C (-22.4 F)
2026-22.6 C (-8.7 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at South Pass by year The wettest day of the year at South Pass, 1985 to 2026. The record is 99.1 mm (3.9 in) in 2011, marked on the chart; the median year is 36.9 mm (1.5 in). 204060801001990200020102020Record: 99.1 mm (3.9 in) in 2011
The wettest day of the year at South Pass, 1985 to 2026. The record is 99.1 mm (3.9 in) in 2011, marked on the chart; the median year is 36.9 mm (1.5 in).
Wettest day (Rx1day) at South Pass by year
YearWettest day (Rx1day)
198558.4 mm (2.3 in)
198668.6 mm (2.7 in)
198733.0 mm (1.3 in)
198825.4 mm (1.0 in)
198938.1 mm (1.5 in)
199030.5 mm (1.2 in)
199145.7 mm (1.8 in)
199230.5 mm (1.2 in)
199330.5 mm (1.2 in)
199435.6 mm (1.4 in)
199543.2 mm (1.7 in)
199645.7 mm (1.8 in)
199748.3 mm (1.9 in)
199840.6 mm (1.6 in)
199971.1 mm (2.8 in)
200035.6 mm (1.4 in)
200130.5 mm (1.2 in)
200225.4 mm (1.0 in)
200340.6 mm (1.6 in)
200435.6 mm (1.4 in)
200543.2 mm (1.7 in)
200625.4 mm (1.0 in)
200743.2 mm (1.7 in)
200830.5 mm (1.2 in)
200935.6 mm (1.4 in)
201063.5 mm (2.5 in)
201199.1 mm (3.9 in)
201225.4 mm (1.0 in)
201327.9 mm (1.1 in)
201440.6 mm (1.6 in)
201525.4 mm (1.0 in)
201653.3 mm (2.1 in)
201761.0 mm (2.4 in)
201830.5 mm (1.2 in)
201927.9 mm (1.1 in)
202033.0 mm (1.3 in)
202135.6 mm (1.4 in)
202238.1 mm (1.5 in)
202338.1 mm (1.5 in)
202438.1 mm (1.5 in)
202543.2 mm (1.7 in)
202625.4 mm (1.0 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at South Pass by year The wettest five days of the year at South Pass, 1985 to 2026. The record is 213.4 mm (8.4 in) in 1986, marked on the chart; the median year is 63.5 mm (2.5 in). 0501001502002501990200020102020Record: 213.4 mm (8.4 in) in 1986
The wettest five days of the year at South Pass, 1985 to 2026. The record is 213.4 mm (8.4 in) in 1986, marked on the chart; the median year is 63.5 mm (2.5 in).
Wettest five days (Rx5day) at South Pass by year
YearWettest five days (Rx5day)
198593.9 mm (3.7 in)
1986213.4 mm (8.4 in)
198755.9 mm (2.2 in)
198850.9 mm (2.0 in)
198968.6 mm (2.7 in)
199068.6 mm (2.7 in)
199199.0 mm (3.9 in)
199255.9 mm (2.2 in)
199348.2 mm (1.9 in)
199488.9 mm (3.5 in)
199571.1 mm (2.8 in)
199686.3 mm (3.4 in)
199763.4 mm (2.5 in)
199858.4 mm (2.3 in)
1999119.3 mm (4.7 in)
200068.5 mm (2.7 in)
200160.9 mm (2.4 in)
200243.2 mm (1.7 in)
200353.3 mm (2.1 in)
200471.2 mm (2.8 in)
200563.5 mm (2.5 in)
200668.7 mm (2.7 in)
200766.0 mm (2.6 in)
200858.4 mm (2.3 in)
200968.5 mm (2.7 in)
2010106.6 mm (4.2 in)
2011134.6 mm (5.3 in)
201245.8 mm (1.8 in)
201353.3 mm (2.1 in)
201453.3 mm (2.1 in)
201553.4 mm (2.1 in)
201699.0 mm (3.9 in)
2017152.4 mm (6.0 in)
201840.6 mm (1.6 in)
201961.0 mm (2.4 in)
202045.7 mm (1.8 in)
202163.4 mm (2.5 in)
202253.3 mm (2.1 in)
202366.1 mm (2.6 in)
202455.9 mm (2.2 in)
202573.7 mm (2.9 in)
202661.0 mm (2.4 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at South Pass by year The longest dry spell of the year at South Pass, 1985 to 2026. The record is 64 days in 2013, marked on the chart; the median year is 30 days. 0204060801990200020102020Record: 64 days in 2013
The longest dry spell of the year at South Pass, 1985 to 2026. The record is 64 days in 2013, marked on the chart; the median year is 30 days.
Longest dry spell (CDD) at South Pass by year
YearLongest dry spell (CDD)
198521 days
198624 days
198724 days
198856 days
198930 days
199031 days
199122 days
199233 days
199316 days
199421 days
199527 days
199646 days
199741 days
199824 days
199922 days
200016 days
200123 days
200254 days
200328 days
200424 days
200533 days
200662 days
200735 days
200836 days
200921 days
201033 days
201154 days
201258 days
201364 days
201425 days
201541 days
201631 days
201731 days
201855 days
201947 days
202027 days
202129 days
202228 days
202314 days
202418 days
202527 days
202630 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

40 years with a frost

Across 40 years with a frost, the median last spring frost at South Pass falls on 23 June and the median first autumn frost on 30 August, which leaves a median of 71 days between them.

Fitted over all years, the growing season changes by +12.2 days per decade at this station.

Frost dates and growing season at South Pass
MeasureMedian, all yearsEarliest periodRecent period (1996 to 2025)Recent against earliestFitted trend
Last spring frost23 Junen/a23 Junen/a-2.3 days per decade
First autumn frost30 Augustn/a1 Septembern/a+9.9 days per decade
Growing days71 daysn/a76 daysn/a+12.2 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

40 years, 1986 to 2025

A day with at least 36.2 mm (1.4 in) of rain is expected about once in 2 years. A day with at least 102.0 mm (4.0 in) of rain is expected about once in 100 years.

Rainfall return levels at South Pass: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years36.2 mm (1.4 in)
5 years47.8 mm (1.9 in)
10 years57.4 mm (2.3 in)
25 years72.4 mm (2.9 in)
50 years86.0 mm (3.4 in)Longer than the 40 years of record
100 years102.0 mm (4.0 in)Longer than the 40 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, 40 years of values from 1986 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: 99.1 mm (3.9 in) in 2011; 71.1 mm (2.8 in) in 1999; 68.6 mm (2.7 in) in 1986.

Station Changes

1 suspected

One change was suspected in the annual mean temperature of South Pass, at 2012. Each is measured against neighbouring stations.

  • Relative to 5 neighbouring stations, the station's annual mean temperature from 2012 ran 0.6 C (1.0 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at South Pass, against neighbouring stations
YearShift (C)Shift (F)StrengthNeighbours
2012-0.6-1.0possible5

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.

Download the Data

  • Data for South Pass standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for South Pass 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).