Built 2026-10-18 (18 October 2026)

Lolo Pass Weather Records (USS0014C05S)

Record envelope, standing records and threshold days for Lolo Pass (USS0014C05S), Idaho, United States, with 44 years of record.

Key Facts for Lolo Pass

  • Lolo Pass (USS0014C05S) is a weather station in Idaho, United States at 46.63 latitude and -114.58 longitude, 1,597 m (5,240 ft) above sea level.
  • The station reports from 1983 to 2026, 44 years of record.
  • 1,464 records set at Lolo Pass still stand.
  • Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
  • Lolo Pass set a daily record high maximum temperature of 23.5 C (74.3 F) on 4 October 2026 (provisional).

Provisional Records

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

About the Station

  • Location: Idaho, United States, 46.63 latitude, -114.58 longitude.
  • Elevation: 1,597 m (5,240 ft).
  • Period of record: 1983 to 2026, 44 years.
  • Eligible elements: tmax, tmin, prcp.

Daily Record Envelope and 2026

17 days at or beyond a record
Daily record high and record low at Lolo Pass, with 2026 drawn through them The band shows the record high and record low for each calendar day at Lolo Pass. The lines show the 2026 daily maximum and minimum. 17 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 Lolo Pass. The lines show the 2026 daily maximum and minimum. 17 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Lolo Pass, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan13.1 C (55.6 F)-35.8 C (-32.4 F)6.3 C (43.3 F)-19.0 C (-2.2 F)
Feb15.1 C (59.2 F)-30.1 C (-22.2 F)12.8 C (55.0 F)-14.9 C (5.2 F)
Mar21.8 C (71.2 F)-23.1 C (-9.6 F)16.0 C (60.8 F)-11.3 C (11.7 F)
Apr26.1 C (79.0 F)-17.0 C (1.4 F)21.1 C (70.0 F)-7.4 C (18.7 F)
May31.5 C (88.7 F)-11.1 C (12.0 F)28.2 C (82.8 F)-3.3 C (26.1 F)
Jun33.9 C (93.0 F)-4.1 C (24.6 F)25.2 C (77.4 F)-2.7 C (27.1 F)
Jul38.7 C (101.7 F)-1.5 C (29.3 F)31.8 C (89.2 F)0.0 C (32.0 F)
Aug35.2 C (95.4 F)-5.6 C (21.9 F)31.9 C (89.4 F)0.6 C (33.1 F)
Sep33.0 C (91.4 F)-10.7 C (12.7 F)25.4 C (77.7 F)-3.3 C (26.1 F)
Oct28.5 C (83.3 F)-22.4 C (-8.3 F)23.5 C (74.3 F)-3.1 C (26.4 F)
Nov17.3 C (63.1 F)-25.9 C (-14.6 F)n/an/a
Dec9.0 C (48.2 F)-36.4 C (-33.5 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Lolo Pass by the year they were set 1,464 records at Lolo Pass still stand. 1996 holds the most, with 54. 02040601983: 271984: 311985: 361986: 451987: 531988: 331989: 241990: 341991: 291992: 321993: 451994: 221995: 341996: 541997: 261998: 271999: 372000: 162001: 242002: 362003: 312004: 422005: 342006: 192007: 252008: 342009: 442010: 282011: 282012: 252013: 362014: 372015: 442016: 422017: 252018: 202019: 372020: 242021: 392022: 512023: 422024: 342025: 342026: 24198319881993199820032008201320182023
1,464 records at Lolo Pass still stand. 1996 holds the most, with 54.
Standing records at Lolo Pass by the year they were set
Year setStanding records
198327
198431
198536
198645
198753
198833
198924
199034
199129
199232
199345
199422
199534
199654
199726
199827
199937
200016
200124
200236
200331
200442
200534
200619
200725
200834
200944
201028
201128
201225
201336
201437
201544
201642
201725
201820
201937
202024
202139
202251
202342
202434
202534
202624

All-Time Record Progression

1 new records
When Lolo Pass set new all-time records 1 all-time records were set at Lolo Pass between 29 June 2015 and 29 June 2015. Each dot is a new record. Record high minimum temperature29 June 2015: Record high minimum temperature 16.6 C (61.9 F)2015
1 all-time records were set at Lolo Pass between 29 June 2015 and 29 June 2015. Each dot is a new record.
When Lolo Pass set new all-time records
DateKindDetail
2015-06-29Record high minimum temperatureRecord high minimum temperature 16.6 C (61.9 F)

Wettest Day of Each Month

Feb: 76.2 mm (3.0 in)
Record daily precipitation for each month at Lolo Pass The wettest day on record for each calendar month at Lolo Pass. The most was 76.2 mm (3.0 in) on 26 February 1983. 020406080 Jan: 55.9 mm (2.2 in), 10 January 2006 Jan Feb: 76.2 mm (3.0 in), 26 February 1983 Feb Mar: 40.6 mm (1.6 in), 7 March 2003 Mar Apr: 38.1 mm (1.5 in), 7 April 2019 Apr May: 35.6 mm (1.4 in), 13 May 1998 May Jun: 48.3 mm (1.9 in), 13 June 1994 Jun Jul: 40.6 mm (1.6 in), 18 July 2002 Jul Aug: 50.8 mm (2.0 in), 20 August 2008 Aug Sep: 38.1 mm (1.5 in), 22 September 2022 Sep Oct: 55.9 mm (2.2 in), 31 October 2015 Oct Nov: 68.6 mm (2.7 in), 7 November 2006 Nov Dec: 61.0 mm (2.4 in), 3 December 2007 Dec
The wettest day on record for each calendar month at Lolo Pass. The most was 76.2 mm (3.0 in) on 26 February 1983.
Record daily precipitation for each month at Lolo Pass
MonthRecord daily precipitation (mm)Date
Jan55.9 mm (2.2 in)10 January 2006
Feb76.2 mm (3.0 in)26 February 1983
Mar40.6 mm (1.6 in)7 March 2003
Apr38.1 mm (1.5 in)7 April 2019
May35.6 mm (1.4 in)13 May 1998
Jun48.3 mm (1.9 in)13 June 1994
Jul40.6 mm (1.6 in)18 July 2002
Aug50.8 mm (2.0 in)20 August 2008
Sep38.1 mm (1.5 in)22 September 2022
Oct55.9 mm (2.2 in)31 October 2015
Nov68.6 mm (2.7 in)7 November 2006
Dec61.0 mm (2.4 in)3 December 2007

Period of Record Coverage

1983 to 2026
Days with data per year at Lolo Pass 44 years of record at Lolo Pass, 1983 to 2026. 6 years have data for under 90 percent of days and are left out of rankings: 1983, 1984, 1985, 1988, 1989, 2026. 1983: 314 of 365 days1984: 296 of 366 days1985: 250 of 365 days1986: 353 of 365 days1987: 350 of 365 days1988: 283 of 366 days1989: 324 of 365 days1990: 358 of 365 days1991: 362 of 365 days1992: 365 of 366 days1993: 350 of 365 days1994: 353 of 365 days1995: 365 of 365 days1996: 363 of 366 days1997: 365 of 365 days1998: 363 of 365 days1999: 364 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: 364 of 365 days2022: 362 of 365 days2023: 365 of 365 days2024: 364 of 366 days2025: 365 of 365 days2026: 267 of 365 days1990200020102020
44 years of record at Lolo Pass, 1983 to 2026. 6 years have data for under 90 percent of days and are left out of rankings: 1983, 1984, 1985, 1988, 1989, 2026.
Days with data per year at Lolo Pass
YearDays with dataShare of yearComplete
198331486%No
198429681%No
198525068%No
198635397%Yes
198735096%Yes
198828377%No
198932489%No
199035898%Yes
199136299%Yes
1992365100%Yes
199335096%Yes
199435397%Yes
1995365100%Yes
199636399%Yes
1997365100%Yes
199836399%Yes
1999364100%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
2021364100%Yes
202236299%Yes
2023365100%Yes
202436499%Yes
2025365100%Yes
202626773%No

Latest Records

20
Latest records at Lolo Pass
DateStationRecordValueBeat old record byOld record stoodSignificance
4 October 2026Lolo Pass, USdaily high max (Provisional)23.5 C (74.3 F)0.3 C (0.5 F)23 years10 of 100 (Routine)
30 September 2026Lolo Pass, USdaily high min (Provisional)8.7 C (47.7 F)0.5 C (0.9 F)20 years11 of 100 (Routine)
15 September 2026Lolo Pass, USdaily low min (Provisional)-1.3 C (29.7 F)0.1 C (0.2 F)35 years14 of 100 (Routine)
14 September 2026Lolo Pass, USdaily low max (Provisional)6.1 C (43.0 F)0.9 C (1.6 F)21 years11 of 100 (Routine)
7 September 2026Lolo Pass, USdaily low max (Provisional)8.0 C (46.4 F)3.2 C (5.8 F)24 years15 of 100 (Routine)
7 September 2026Lolo Pass, USdaily rain (Tie, Provisional)12.7 mm (0.5 in)tie40 years4 of 100 (Routine)
2 September 2026Lolo Pass, USdaily rain (Tie, Provisional)2.5 mm (0.10 in)tie40 years4 of 100 (Routine)
22 August 2026Lolo Pass, USdaily high min (Provisional)14.0 C (57.2 F)2.7 C (4.9 F)23 years19 of 100 (Routine)
22 August 2026Lolo Pass, USdaily high max (Provisional)31.0 C (87.8 F)0.6 C (1.1 F)15 years9 of 100 (Routine)
21 August 2026Lolo Pass, USdaily high max (Tie, Provisional)31.9 C (89.4 F)tie20 years2 of 100 (Routine)
20 August 2026Lolo Pass, USdaily high max (Provisional)30.6 C (87.1 F)1.0 C (1.8 F)7 years7 of 100 (Routine)
14 August 2026Lolo Pass, USdaily rain15.2 mm (0.6 in)10.1 mm (0.4 in)39 years20 of 100 (Routine)
28 July 2026Lolo Pass, USdaily low min0.0 C (32.0 F)2.4 C (4.3 F)40 years23 of 100 (Routine)
21 July 2026Lolo Pass, USdaily high min12.9 C (55.2 F)0.1 C (0.2 F)1 year4 of 100 (Routine)
17 July 2026Lolo Pass, USdaily high min13.7 C (56.7 F)1.8 C (3.2 F)19 years14 of 100 (Routine)
29 June 2026Lolo Pass, USdaily low max7.4 C (45.3 F)0.4 C (0.7 F)5 years5 of 100 (Routine)
28 June 2026Lolo Pass, USdaily low max5.6 C (42.1 F)3.7 C (6.7 F)32 years18 of 100 (Routine)
27 June 2026Lolo Pass, USdaily low max9.6 C (49.3 F)2.4 C (4.3 F)12 years10 of 100 (Routine)
16 June 2026Lolo Pass, USdaily high min9.8 C (49.6 F)3.2 C (5.8 F)28 years21 of 100 (Routine)
8 June 2026Lolo Pass, USdaily low min-2.7 C (27.1 F)1.5 C (2.7 F)27 years16 of 100 (Routine)

Climate Trend

37 complete years, 1986 to 2025
Annual mean temperature at Lolo Pass as warming stripes, 1986 to 2025 One stripe for each of 37 complete years at Lolo Pass, 1986 to 2025. Blue stripes are years cooler than the station's own mean of 3.8 C (38.8 F); red stripes are warmer. The coolest year was 1993, at 1.8 C (35.3 F), and the warmest was 2015, at 5.5 C (41.8 F). The strongest colour marks a difference of 2.0 C (3.6 F). 1986: 3.8 C, 0.0 C from the station mean1990: 3.5 C, -0.3 C from the station mean1991: 3.0 C, -0.8 C from the station mean1992: 3.7 C, -0.1 C from the station mean1993: 1.8 C, -2.0 C from the station mean1994: 3.5 C, -0.3 C from the station mean1995: 2.6 C, -1.2 C from the station mean1996: 2.4 C, -1.4 C from the station mean1997: 2.5 C, -1.3 C from the station mean1998: 3.8 C, +0.1 C from the station mean1999: 3.2 C, -0.6 C from the station mean2000: 3.6 C, -0.2 C from the station mean2001: 4.0 C, +0.3 C from the station mean2002: 3.1 C, -0.7 C from the station mean2003: 4.4 C, +0.6 C from the station mean2004: 4.8 C, +1.0 C from the station mean2005: 3.5 C, -0.2 C from the station mean2006: 4.1 C, +0.3 C from the station mean2007: 4.6 C, +0.8 C from the station mean2008: 3.0 C, -0.7 C from the station mean2009: 3.2 C, -0.6 C from the station mean2010: 3.7 C, -0.1 C from the station mean2011: 3.3 C, -0.5 C from the station mean2012: 4.4 C, +0.6 C from the station mean2013: 4.1 C, +0.3 C from the station mean2014: 4.0 C, +0.2 C from the station mean2015: 5.5 C, +1.7 C from the station mean2016: 4.8 C, +1.0 C from the station mean2017: 4.4 C, +0.6 C from the station mean2018: 4.1 C, +0.3 C from the station mean2019: 3.3 C, -0.5 C from the station mean2020: 4.1 C, +0.3 C from the station mean2021: 4.5 C, +0.7 C from the station mean2022: 3.9 C, +0.1 C from the station mean2023: 4.5 C, +0.7 C from the station mean2024: 4.8 C, +1.0 C from the station mean2025: 4.9 C, +1.1 C from the station mean198619901995200020052010201520202025
One stripe for each of 37 complete years at Lolo Pass, 1986 to 2025. Blue stripes are years cooler than the station's own mean of 3.8 C (38.8 F); red stripes are warmer. The coolest year was 1993, at 1.8 C (35.3 F), and the warmest was 2015, at 5.5 C (41.8 F). The strongest colour marks a difference of 2.0 C (3.6 F).
Annual mean temperature at Lolo Pass as warming stripes, 1986 to 2025
YearAnnual mean temperatureDifference from the station mean
19863.8 C+0.01 C
19903.5 C-0.26 C
19913.0 C-0.81 C
19923.7 C-0.14 C
19931.8 C-1.97 C
19943.5 C-0.32 C
19952.6 C-1.23 C
19962.4 C-1.44 C
19972.5 C-1.27 C
19983.8 C+0.05 C
19993.2 C-0.60 C
20003.6 C-0.23 C
20014.0 C+0.25 C
20023.1 C-0.66 C
20034.4 C+0.61 C
20044.8 C+1.04 C
20053.5 C-0.25 C
20064.1 C+0.32 C
20074.6 C+0.76 C
20083.0 C-0.75 C
20093.2 C-0.61 C
20103.7 C-0.11 C
20113.3 C-0.52 C
20124.4 C+0.62 C
20134.1 C+0.29 C
20144.0 C+0.22 C
20155.5 C+1.66 C
20164.8 C+1.01 C
20174.4 C+0.58 C
20184.1 C+0.29 C
20193.3 C-0.52 C
20204.1 C+0.28 C
20214.5 C+0.71 C
20223.9 C+0.13 C
20234.5 C+0.70 C
20244.8 C+0.99 C
20254.9 C+1.13 C

The annual mean temperature here has risen by 0.4 C (0.2 to 0.6) per decade over 1986 to 2025. In Fahrenheit: 0.8 F (0.4 to 1.1) per decade. The slope is a straight line fitted to 37 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Lolo Pass
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.4 C (0.2 to 0.6) per decade0.8 F (0.4 to 1.1) per decade1986 to 202537Rise
Mean daily maximum0.4 C (0.2 to 0.7) per decade0.7 F (0.3 to 1.2) per decade1986 to 202537Rise
Mean daily minimum0.5 C (0.3 to 0.6) per decade0.8 F (0.5 to 1.1) per decade1986 to 202537Rise

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

1983 to 2026
Yearly extremes at Lolo Pass: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)38.7 C (101.7 F)200432.8 C (91.0 F)44
Coldest night (TNn)-36.4 C (-33.5 F)1990-25.2 C (-13.4 F)44
Wettest day (Rx1day)76.2 mm (3.0 in)198338.1 mm (1.5 in)44
Wettest five days (Rx5day)177.9 mm (7.0 in)199596.5 mm (3.8 in)44
Longest dry spell (CDD)55 days201226 days44

Hottest day (TXx)

Hottest day (TXx) at Lolo Pass by year The hottest day of the year at Lolo Pass, 1983 to 2026. The record is 38.7 C (101.7 F) in 2004, marked on the chart; the median year is 32.8 C (91.0 F). 20253035401990200020102020Record: 38.7 C (101.7 F) in 2004
The hottest day of the year at Lolo Pass, 1983 to 2026. The record is 38.7 C (101.7 F) in 2004, marked on the chart; the median year is 32.8 C (91.0 F).
Hottest day (TXx) at Lolo Pass by year
YearHottest day (TXx)
198333.8 C (92.8 F)
198433.4 C (92.1 F)
198523.1 C (73.6 F)
198632.7 C (90.9 F)
198732.7 C (90.9 F)
198833.0 C (91.4 F)
198933.5 C (92.3 F)
199033.2 C (91.8 F)
199132.6 C (90.7 F)
199232.2 C (90.0 F)
199329.5 C (85.1 F)
199432.5 C (90.5 F)
199529.4 C (84.9 F)
199632.7 C (90.9 F)
199730.6 C (87.1 F)
199833.6 C (92.5 F)
199932.3 C (90.1 F)
200033.1 C (91.6 F)
200132.4 C (90.3 F)
200235.9 C (96.6 F)
200334.4 C (93.9 F)
200438.7 C (101.7 F)
200531.9 C (89.4 F)
200633.4 C (92.1 F)
200735.6 C (96.1 F)
200833.4 C (92.1 F)
200932.8 C (91.0 F)
201031.3 C (88.3 F)
201130.7 C (87.3 F)
201232.8 C (91.0 F)
201332.8 C (91.0 F)
201432.3 C (90.1 F)
201533.9 C (93.0 F)
201631.3 C (88.3 F)
201733.3 C (91.9 F)
201835.2 C (95.4 F)
201931.7 C (89.1 F)
202031.7 C (89.1 F)
202133.1 C (91.6 F)
202233.1 C (91.6 F)
202332.8 C (91.0 F)
202433.6 C (92.5 F)
202530.6 C (87.1 F)
202631.9 C (89.4 F)

Coldest night (TNn)

Coldest night (TNn) at Lolo Pass by year The coldest night of the year at Lolo Pass, 1983 to 2026. The record is -36.4 C (-33.5 F) in 1990, marked on the chart; the median year is -25.2 C (-13.4 F). -40-35-30-25-20-151990200020102020Record: -36.4 C (-33.5 F) in 1990
The coldest night of the year at Lolo Pass, 1983 to 2026. The record is -36.4 C (-33.5 F) in 1990, marked on the chart; the median year is -25.2 C (-13.4 F).
Coldest night (TNn) at Lolo Pass by year
YearColdest night (TNn)
1983-28.2 C (-18.8 F)
1984-23.2 C (-9.8 F)
1985-30.1 C (-22.2 F)
1986-22.5 C (-8.5 F)
1987-25.1 C (-13.2 F)
1988-24.0 C (-11.2 F)
1989-22.6 C (-8.7 F)
1990-36.4 C (-33.5 F)
1991-26.5 C (-15.7 F)
1992-22.0 C (-7.6 F)
1993-27.3 C (-17.1 F)
1994-26.8 C (-16.2 F)
1995-24.3 C (-11.7 F)
1996-28.8 C (-19.8 F)
1997-24.4 C (-11.9 F)
1998-34.1 C (-29.4 F)
1999-18.2 C (-0.8 F)
2000-18.9 C (-2.0 F)
2001-19.7 C (-3.5 F)
2002-22.4 C (-8.3 F)
2003-24.8 C (-12.6 F)
2004-27.5 C (-17.5 F)
2005-24.5 C (-12.1 F)
2006-28.3 C (-18.9 F)
2007-29.4 C (-20.9 F)
2008-28.1 C (-18.6 F)
2009-27.1 C (-16.8 F)
2010-26.4 C (-15.5 F)
2011-26.1 C (-15.0 F)
2012-18.0 C (-0.4 F)
2013-27.1 C (-16.8 F)
2014-30.1 C (-22.2 F)
2015-19.3 C (-2.7 F)
2016-23.3 C (-9.9 F)
2017-25.3 C (-13.5 F)
2018-20.8 C (-5.4 F)
2019-23.1 C (-9.6 F)
2020-20.6 C (-5.1 F)
2021-24.3 C (-11.7 F)
2022-31.7 C (-25.1 F)
2023-28.3 C (-18.9 F)
2024-35.8 C (-32.4 F)
2025-25.9 C (-14.6 F)
2026-19.0 C (-2.2 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Lolo Pass by year The wettest day of the year at Lolo Pass, 1983 to 2026. The record is 76.2 mm (3.0 in) in 1983, marked on the chart; the median year is 38.1 mm (1.5 in). 204060801990200020102020Record: 76.2 mm (3.0 in) in 1983
The wettest day of the year at Lolo Pass, 1983 to 2026. The record is 76.2 mm (3.0 in) in 1983, marked on the chart; the median year is 38.1 mm (1.5 in).
Wettest day (Rx1day) at Lolo Pass by year
YearWettest day (Rx1day)
198376.2 mm (3.0 in)
198445.7 mm (1.8 in)
198530.5 mm (1.2 in)
198638.1 mm (1.5 in)
198733.0 mm (1.3 in)
198848.3 mm (1.9 in)
198938.1 mm (1.5 in)
199035.6 mm (1.4 in)
199150.8 mm (2.0 in)
199238.1 mm (1.5 in)
199330.5 mm (1.2 in)
199450.8 mm (2.0 in)
199545.7 mm (1.8 in)
199640.6 mm (1.6 in)
199748.3 mm (1.9 in)
199845.7 mm (1.8 in)
199938.1 mm (1.5 in)
200040.6 mm (1.6 in)
200135.6 mm (1.4 in)
200240.6 mm (1.6 in)
200345.7 mm (1.8 in)
200438.1 mm (1.5 in)
200530.5 mm (1.2 in)
200668.6 mm (2.7 in)
200761.0 mm (2.4 in)
200850.8 mm (2.0 in)
200933.0 mm (1.3 in)
201035.6 mm (1.4 in)
201140.6 mm (1.6 in)
201243.2 mm (1.7 in)
201335.6 mm (1.4 in)
201435.6 mm (1.4 in)
201555.9 mm (2.2 in)
201633.0 mm (1.3 in)
201740.6 mm (1.6 in)
201838.1 mm (1.5 in)
201938.1 mm (1.5 in)
202030.5 mm (1.2 in)
202133.0 mm (1.3 in)
202238.1 mm (1.5 in)
202327.9 mm (1.1 in)
202435.6 mm (1.4 in)
202535.6 mm (1.4 in)
202638.1 mm (1.5 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Lolo Pass by year The wettest five days of the year at Lolo Pass, 1983 to 2026. The record is 177.9 mm (7.0 in) in 1995, marked on the chart; the median year is 96.5 mm (3.8 in). 501001502001990200020102020Record: 177.9 mm (7.0 in) in 1995
The wettest five days of the year at Lolo Pass, 1983 to 2026. The record is 177.9 mm (7.0 in) in 1995, marked on the chart; the median year is 96.5 mm (3.8 in).
Wettest five days (Rx5day) at Lolo Pass by year
YearWettest five days (Rx5day)
1983152.4 mm (6.0 in)
198481.4 mm (3.2 in)
198596.6 mm (3.8 in)
1986122.0 mm (4.8 in)
198781.2 mm (3.2 in)
1988116.9 mm (4.6 in)
198996.5 mm (3.8 in)
1990104.2 mm (4.1 in)
199183.9 mm (3.3 in)
199281.3 mm (3.2 in)
199371.1 mm (2.8 in)
1994122.0 mm (4.8 in)
1995177.9 mm (7.0 in)
1996129.4 mm (5.1 in)
199791.5 mm (3.6 in)
1998121.9 mm (4.8 in)
199996.5 mm (3.8 in)
200073.6 mm (2.9 in)
200176.2 mm (3.0 in)
200283.9 mm (3.3 in)
2003116.9 mm (4.6 in)
200486.4 mm (3.4 in)
200568.6 mm (2.7 in)
2006152.4 mm (6.0 in)
200794.0 mm (3.7 in)
200896.4 mm (3.8 in)
2009101.6 mm (4.0 in)
201073.7 mm (2.9 in)
2011127.0 mm (5.0 in)
201296.5 mm (3.8 in)
201361.0 mm (2.4 in)
2014104.2 mm (4.1 in)
2015109.2 mm (4.3 in)
201678.7 mm (3.1 in)
201796.5 mm (3.8 in)
2018101.6 mm (4.0 in)
201991.4 mm (3.6 in)
202078.7 mm (3.1 in)
202171.2 mm (2.8 in)
202288.8 mm (3.5 in)
202363.5 mm (2.5 in)
202463.5 mm (2.5 in)
2025121.9 mm (4.8 in)
2026104.2 mm (4.1 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Lolo Pass by year The longest dry spell of the year at Lolo Pass, 1983 to 2026. The record is 55 days in 2012, marked on the chart; the median year is 26 days. 02040601990200020102020Record: 55 days in 2012
The longest dry spell of the year at Lolo Pass, 1983 to 2026. The record is 55 days in 2012, marked on the chart; the median year is 26 days.
Longest dry spell (CDD) at Lolo Pass by year
YearLongest dry spell (CDD)
198327 days
198436 days
198548 days
198626 days
198745 days
198826 days
198911 days
199025 days
199131 days
199216 days
199320 days
199425 days
199522 days
199620 days
199713 days
199815 days
199927 days
200054 days
200134 days
200214 days
200325 days
200415 days
200532 days
200632 days
200720 days
200831 days
200913 days
201019 days
201119 days
201255 days
201322 days
201418 days
201532 days
201624 days
201731 days
201847 days
201923 days
202026 days
202130 days
202225 days
202331 days
202428 days
202516 days
202644 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

37 years with a frost

Across 37 years with a frost, the median last spring frost at Lolo Pass falls on 16 June and the median first autumn frost on 31 August, which leaves a median of 74 days between them.

Fitted over all years, the growing season changes by +13.0 days per decade at this station.

Frost dates and growing season at Lolo Pass
MeasureMedian, all yearsEarliest periodRecent period (1996 to 2025)Recent against earliestFitted trend
Last spring frost16 Junen/a16 Junen/a-2.4 days per decade
First autumn frost31 Augustn/a2 Septembern/a+10.6 days per decade
Growing days74 daysn/a75 daysn/a+13.0 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, 1983 to 2025

A day with at least 38.5 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 81.8 mm (3.2 in) of rain is expected about once in 100 years.

Rainfall return levels at Lolo Pass: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years38.5 mm (1.5 in)
5 years46.8 mm (1.8 in)
10 years53.4 mm (2.1 in)
25 years63.3 mm (2.5 in)
50 years71.9 mm (2.8 in)Longer than the 42 years of record
100 years81.8 mm (3.2 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 1983 to 2025.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 76.2 mm (3.0 in) in 1983; 68.6 mm (2.7 in) in 2006; 61.0 mm (2.4 in) in 2007.

Download the Data

  • Data for Lolo Pass standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Lolo 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-16).