Built 2026-10-15 (15 October 2026)

Aspen 1SW Weather Records (USC00050372)

Record envelope, standing records and threshold days for Aspen 1SW (USC00050372), Colorado, United States, with 47 years of record.

Key Facts for Aspen 1SW

  • Aspen 1SW (USC00050372) is a weather station in Colorado, United States at 39.19 latitude and -106.84 longitude, 2,492 m (8,175 ft) above sea level.
  • The station reports from 1980 to 2026, 47 years of record.
  • 1,464 records set at Aspen 1SW still stand.
  • Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
  • Aspen 1SW tied a daily record low maximum temperature of 18.3 C (64.9 F) on 31 August 2026 (provisional).

Provisional Records

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

About the Station

  • Location: Colorado, United States, 39.19 latitude, -106.84 longitude.
  • Elevation: 2,492 m (8,175 ft).
  • Period of record: 1980 to 2026, 47 years.
  • Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

31 days at or beyond a record
Daily record high and record low at Aspen 1SW, with 2026 drawn through them The band shows the record high and record low for each calendar day at Aspen 1SW. The lines show the 2026 daily maximum and minimum. 31 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 Aspen 1SW. The lines show the 2026 daily maximum and minimum. 31 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Aspen 1SW, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan14.4 C (57.9 F)-28.9 C (-20.0 F)11.1 C (52.0 F)-22.2 C (-8.0 F)
Feb15.6 C (60.1 F)-31.7 C (-25.1 F)11.1 C (52.0 F)-15.6 C (3.9 F)
Mar22.8 C (73.0 F)-25.6 C (-14.1 F)22.8 C (73.0 F)-10.6 C (12.9 F)
Apr23.3 C (73.9 F)-17.8 C (0.0 F)21.1 C (70.0 F)-8.9 C (16.0 F)
May30.0 C (86.0 F)-9.4 C (15.1 F)25.0 C (77.0 F)-4.4 C (24.1 F)
Jun31.1 C (88.0 F)-6.7 C (19.9 F)28.3 C (82.9 F)0.6 C (33.1 F)
Jul32.8 C (91.0 F)-1.7 C (28.9 F)31.7 C (89.1 F)5.6 C (42.1 F)
Aug32.2 C (90.0 F)-1.7 C (28.9 F)32.2 C (90.0 F)5.6 C (42.1 F)
Sep30.0 C (86.0 F)-7.8 C (18.0 F)n/an/a
Oct25.6 C (78.1 F)-20.6 C (-5.1 F)n/an/a
Nov21.1 C (70.0 F)-25.0 C (-13.0 F)n/an/a
Dec16.7 C (62.1 F)-30.6 C (-23.1 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Aspen 1SW by the year they were set 1,464 records at Aspen 1SW still stand. 2000 holds the most, with 51. 02040601980: 231981: 261982: 371983: 261984: 341985: 441986: 221987: 331988: 341989: 461990: 391991: 281992: 401993: 411994: 131995: 311996: 371997: 221998: 341999: 392000: 512001: 202002: 362003: 412004: 232005: 252006: 322007: 272008: 252009: 342010: 302011: 292012: 252013: 432014: 252015: 302016: 222017: 232018: 222019: 302020: 362021: 302022: 222023: 222024: 222025: 442026: 461980198519901995200020052010201520202025
1,464 records at Aspen 1SW still stand. 2000 holds the most, with 51.
Standing records at Aspen 1SW by the year they were set
Year setStanding records
198023
198126
198237
198326
198434
198544
198622
198733
198834
198946
199039
199128
199240
199341
199413
199531
199637
199722
199834
199939
200051
200120
200236
200341
200423
200525
200632
200727
200825
200934
201030
201129
201225
201343
201425
201530
201622
201723
201822
201930
202036
202130
202222
202322
202422
202544
202646

All-Time Record Progression

2 new records
When Aspen 1SW set new all-time records 2 all-time records were set at Aspen 1SW between 1 January 2011 and 26 July 2026. Each dot is a new record. Record low maximum temperatureRecord high minimum temperature1 January 2011: Record low maximum temperature -16.7 C (1.9 F)26 July 2026: Record high minimum temperature 15.6 C (60.1 F)201520202025
2 all-time records were set at Aspen 1SW between 1 January 2011 and 26 July 2026. Each dot is a new record.
When Aspen 1SW set new all-time records
DateKindDetail
2011-01-01Record low maximum temperatureRecord low maximum temperature -16.7 C (1.9 F)
2026-07-26Record high minimum temperatureRecord high minimum temperature 15.6 C (60.1 F)

Wettest Day of Each Month

Jun: 59.7 mm (2.4 in)
Record daily precipitation for each month at Aspen 1SW The wettest day on record for each calendar month at Aspen 1SW. The most was 59.7 mm (2.4 in) on 7 June 1984. 0204060 Jan: 55.9 mm (2.2 in), 31 January 2014 Jan Feb: 48.8 mm (1.9 in), 21 February 1996 Feb Mar: 40.6 mm (1.6 in), 28 March 1993 Mar Apr: 35.8 mm (1.4 in), 8 April 2018 Apr May: 33.0 mm (1.3 in), 17 May 1983 May Jun: 59.7 mm (2.4 in), 7 June 1984 Jun Jul: 30.5 mm (1.2 in), 25 July 2005 Jul Aug: 33.0 mm (1.3 in), 2 August 2022 Aug Sep: 27.2 mm (1.1 in), 17 September 2007 Sep Oct: 37.6 mm (1.5 in), 29 October 2023 Oct Nov: 45.7 mm (1.8 in), 9 November 1988 Nov Dec: 37.6 mm (1.5 in), 17 December 2016 Dec
The wettest day on record for each calendar month at Aspen 1SW. The most was 59.7 mm (2.4 in) on 7 June 1984.
Record daily precipitation for each month at Aspen 1SW
MonthRecord daily precipitation (mm)Date
Jan55.9 mm (2.2 in)31 January 2014
Feb48.8 mm (1.9 in)21 February 1996
Mar40.6 mm (1.6 in)28 March 1993
Apr35.8 mm (1.4 in)8 April 2018
May33.0 mm (1.3 in)17 May 1983
Jun59.7 mm (2.4 in)7 June 1984
Jul30.5 mm (1.2 in)25 July 2005
Aug33.0 mm (1.3 in)2 August 2022
Sep27.2 mm (1.1 in)17 September 2007
Oct37.6 mm (1.5 in)29 October 2023
Nov45.7 mm (1.8 in)9 November 1988
Dec37.6 mm (1.5 in)17 December 2016

Period of Record Coverage

1980 to 2026
Days with data per year at Aspen 1SW 47 years of record at Aspen 1SW, 1980 to 2026. 3 years have data for under 90 percent of days and are left out of rankings: 1980, 1986, 2026. 1980: 184 of 366 days1981: 365 of 365 days1982: 362 of 365 days1983: 361 of 365 days1984: 365 of 366 days1985: 362 of 365 days1986: 324 of 365 days1987: 359 of 365 days1988: 356 of 366 days1989: 361 of 365 days1990: 364 of 365 days1991: 364 of 365 days1992: 364 of 366 days1993: 330 of 365 days1994: 334 of 365 days1995: 334 of 365 days1996: 333 of 366 days1997: 356 of 365 days1998: 331 of 365 days1999: 365 of 365 days2000: 365 of 366 days2001: 363 of 365 days2002: 362 of 365 days2003: 363 of 365 days2004: 366 of 366 days2005: 363 of 365 days2006: 358 of 365 days2007: 363 of 365 days2008: 361 of 366 days2009: 365 of 365 days2010: 363 of 365 days2011: 365 of 365 days2012: 336 of 366 days2013: 365 of 365 days2014: 364 of 365 days2015: 365 of 365 days2016: 365 of 366 days2017: 365 of 365 days2018: 365 of 365 days2019: 353 of 365 days2020: 366 of 366 days2021: 365 of 365 days2022: 365 of 365 days2023: 365 of 365 days2024: 366 of 366 days2025: 365 of 365 days2026: 243 of 365 days19801990200020102020
47 years of record at Aspen 1SW, 1980 to 2026. 3 years have data for under 90 percent of days and are left out of rankings: 1980, 1986, 2026.
Days with data per year at Aspen 1SW
YearDays with dataShare of yearComplete
198018450%No
1981365100%Yes
198236299%Yes
198336199%Yes
1984365100%Yes
198536299%Yes
198632489%No
198735998%Yes
198835697%Yes
198936199%Yes
1990364100%Yes
1991364100%Yes
199236499%Yes
199333090%Yes
199433492%Yes
199533492%Yes
199633391%Yes
199735698%Yes
199833191%Yes
1999365100%Yes
2000365100%Yes
200136399%Yes
200236299%Yes
200336399%Yes
2004366100%Yes
200536399%Yes
200635898%Yes
200736399%Yes
200836199%Yes
2009365100%Yes
201036399%Yes
2011365100%Yes
201233692%Yes
2013365100%Yes
2014364100%Yes
2015365100%Yes
2016365100%Yes
2017365100%Yes
2018365100%Yes
201935397%Yes
2020366100%Yes
2021365100%Yes
2022365100%Yes
2023365100%Yes
2024366100%Yes
2025365100%Yes
202624367%No

Latest Records

20
Latest records at Aspen 1SW
DateStationRecordValueBeat old record byOld record stoodSignificance
31 August 2026Aspen 1SW, USdaily low max (Tie, Provisional)18.3 C (64.9 F)tie0 years1 of 100 (Routine)
29 August 2026Aspen 1SW, USdaily high max (Tie, Provisional)28.9 C (84.0 F)tie36 years3 of 100 (Routine)
28 August 2026Aspen 1SW, USdaily high min (Provisional)12.2 C (54.0 F)2.2 C (4.0 F)15 years18 of 100 (Routine)
22 August 2026Aspen 1SW, USdaily high min (Provisional)12.8 C (55.0 F)0.6 C (1.1 F)0 years6 of 100 (Routine)
22 August 2026Aspen 1SW, USdaily high max (Tie, Provisional)30.6 C (87.1 F)tie0 years1 of 100 (Routine)
20 August 2026Aspen 1SW, USdaily high min (Tie, Provisional)12.2 C (54.0 F)tie40 years4 of 100 (Routine)
20 August 2026Aspen 1SW, USdaily high max (Tie, Provisional)28.9 C (84.0 F)tie24 years2 of 100 (Routine)
10 August 2026Aspen 1SW, USdaily high min12.8 C (55.0 F)0.6 C (1.1 F)4 years7 of 100 (Routine)
9 August 2026Aspen 1SW, USdaily high min12.8 C (55.0 F)1.1 C (2.0 F)43 years21 of 100 (Routine)
9 August 2026Aspen 1SW, USdaily high max (Tie)30.0 C (86.0 F)tie25 years2 of 100 (Routine)
8 August 2026Aspen 1SW, USdaily high max30.6 C (87.1 F)1.2 C (2.2 F)31 years17 of 100 (Routine)
5 August 2026Aspen 1SW, USdaily high max (Tie)29.4 C (84.9 F)tie32 years3 of 100 (Routine)
4 August 2026Aspen 1SW, USmonthly high max32.2 C (90.0 F)1.1 C (2.0 F)37 years28 of 100 (Routine)
3 August 2026Aspen 1SW, USdaily high min13.9 C (57.0 F)1.7 C (3.1 F)25 years19 of 100 (Routine)
3 August 2026Aspen 1SW, USmonthly high max (Tie)31.1 C (88.0 F)tie37 years6 of 100 (Routine)
1 August 2026Aspen 1SW, USdaily high max28.9 C (84.0 F)0.6 C (1.1 F)40 years18 of 100 (Routine)
28 July 2026Aspen 1SW, USdaily high max (Tie)28.9 C (84.0 F)tie35 years3 of 100 (Routine)
27 July 2026Aspen 1SW, USdaily high max30.6 C (87.1 F)0.6 C (1.1 F)23 years11 of 100 (Routine)
26 July 2026Aspen 1SW, USall-time high min15.6 C (60.1 F)0.6 C (1.1 F)46 years39 of 100 (Notable)
25 July 2026Aspen 1SW, USdaily high min13.9 C (57.0 F)1.7 C (3.1 F)37 years22 of 100 (Routine)

Climate Trend

37 complete years, 1981 to 2025
Annual mean temperature at Aspen 1SW as warming stripes, 1981 to 2025 One stripe for each of 37 complete years at Aspen 1SW, 1981 to 2025. Blue stripes are years cooler than the station's own mean of 5.4 C (41.7 F); red stripes are warmer. The coolest year was 1982, at 3.9 C (39.1 F), and the warmest was 2007, at 6.4 C (43.6 F). The strongest colour marks a difference of 1.5 C (2.7 F). 1981: 5.7 C, +0.3 C from the station mean1982: 3.9 C, -1.5 C from the station mean1983: 4.7 C, -0.7 C from the station mean1984: 4.2 C, -1.2 C from the station mean1985: 4.8 C, -0.6 C from the station mean1987: 5.3 C, -0.1 C from the station mean1988: 5.3 C, -0.1 C from the station mean1989: 5.4 C, 0.0 C from the station mean1990: 5.5 C, +0.1 C from the station mean1991: 5.1 C, -0.3 C from the station mean1992: 4.3 C, -1.1 C from the station mean1997: 5.0 C, -0.4 C from the station mean1999: 6.3 C, +0.9 C from the station mean2000: 6.4 C, +1.0 C from the station mean2001: 6.3 C, +0.9 C from the station mean2002: 5.8 C, +0.5 C from the station mean2003: 6.4 C, +1.0 C from the station mean2004: 5.8 C, +0.4 C from the station mean2005: 5.9 C, +0.6 C from the station mean2006: 5.9 C, +0.5 C from the station mean2007: 6.4 C, +1.0 C from the station mean2008: 5.0 C, -0.4 C from the station mean2009: 5.3 C, -0.1 C from the station mean2010: 5.4 C, 0.0 C from the station mean2011: 4.5 C, -0.9 C from the station mean2013: 4.3 C, -1.1 C from the station mean2014: 5.0 C, -0.4 C from the station mean2015: 5.8 C, +0.4 C from the station mean2016: 5.5 C, +0.2 C from the station mean2017: 6.1 C, +0.7 C from the station mean2018: 5.6 C, +0.2 C from the station mean2020: 5.2 C, -0.2 C from the station mean2021: 5.8 C, +0.4 C from the station mean2022: 4.7 C, -0.7 C from the station mean2023: 4.8 C, -0.6 C from the station mean2024: 5.8 C, +0.4 C from the station mean2025: 6.4 C, +1.0 C from the station mean1981198519901995200020052010201520202025
One stripe for each of 37 complete years at Aspen 1SW, 1981 to 2025. Blue stripes are years cooler than the station's own mean of 5.4 C (41.7 F); red stripes are warmer. The coolest year was 1982, at 3.9 C (39.1 F), and the warmest was 2007, at 6.4 C (43.6 F). The strongest colour marks a difference of 1.5 C (2.7 F).
Annual mean temperature at Aspen 1SW as warming stripes, 1981 to 2025
YearAnnual mean temperatureDifference from the station mean
19815.7 C+0.29 C
19823.9 C-1.47 C
19834.7 C-0.72 C
19844.2 C-1.20 C
19854.8 C-0.60 C
19875.3 C-0.11 C
19885.3 C-0.08 C
19895.4 C-0.01 C
19905.5 C+0.13 C
19915.1 C-0.34 C
19924.3 C-1.12 C
19975.0 C-0.41 C
19996.3 C+0.86 C
20006.4 C+0.99 C
20016.3 C+0.88 C
20025.8 C+0.45 C
20036.4 C+1.01 C
20045.8 C+0.40 C
20055.9 C+0.55 C
20065.9 C+0.49 C
20076.4 C+1.03 C
20085.0 C-0.37 C
20095.3 C-0.08 C
20105.4 C+0.03 C
20114.5 C-0.88 C
20134.3 C-1.12 C
20145.0 C-0.41 C
20155.8 C+0.43 C
20165.5 C+0.15 C
20176.1 C+0.69 C
20185.6 C+0.19 C
20205.2 C-0.17 C
20215.8 C+0.40 C
20224.7 C-0.70 C
20234.8 C-0.60 C
20245.8 C+0.36 C
20256.4 C+0.97 C

The fitted trend in annual mean temperature here over 1981 to 2025 is 0.14 C (-0.02 to 0.31) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.26 F (-0.04 to 0.55) 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 Aspen 1SW
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.14 C (-0.02 to 0.31) per decade0.26 F (-0.04 to 0.55) per decade1981 to 202537Not clearly different from zero
Mean daily maximum-0.04 C (-0.26 to 0.18) per decade-0.1 F (-0.5 to 0.3) per decade1981 to 202537Not clearly different from zero
Mean daily minimum0.3 C (0.2 to 0.5) per decade0.6 F (0.3 to 0.9) per decade1981 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

1980 to 2026
Yearly extremes at Aspen 1SW: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)32.8 C (91.0 F)198930.0 C (86.0 F)47
Coldest night (TNn)-31.7 C (-25.1 F)1989-23.9 C (-11.0 F)47
Wettest day (Rx1day)59.7 mm (2.4 in)198428.4 mm (1.1 in)47
Wettest five days (Rx5day)91.4 mm (3.6 in)198452.1 mm (2.1 in)47
Longest dry spell (CDD)51 days200223 days47

Hottest day (TXx)

Hottest day (TXx) at Aspen 1SW by year The hottest day of the year at Aspen 1SW, 1980 to 2026. The record is 32.8 C (91.0 F) in 1989, marked on the chart; the median year is 30.0 C (86.0 F). 262830323419801990200020102020Record: 32.8 C (91.0 F) in 1989
The hottest day of the year at Aspen 1SW, 1980 to 2026. The record is 32.8 C (91.0 F) in 1989, marked on the chart; the median year is 30.0 C (86.0 F).
Hottest day (TXx) at Aspen 1SW by year
YearHottest day (TXx)
198028.3 C (82.9 F)
198128.3 C (82.9 F)
198228.9 C (84.0 F)
198328.9 C (84.0 F)
198427.8 C (82.0 F)
198531.1 C (88.0 F)
198628.9 C (84.0 F)
198731.1 C (88.0 F)
198831.1 C (88.0 F)
198932.8 C (91.0 F)
199031.1 C (88.0 F)
199129.4 C (84.9 F)
199228.3 C (82.9 F)
199328.3 C (82.9 F)
199429.4 C (84.9 F)
199530.0 C (86.0 F)
199628.9 C (84.0 F)
199729.4 C (84.9 F)
199831.7 C (89.1 F)
199929.4 C (84.9 F)
200030.6 C (87.1 F)
200130.0 C (86.0 F)
200231.1 C (88.0 F)
200331.7 C (89.1 F)
200431.1 C (88.0 F)
200531.7 C (89.1 F)
200630.0 C (86.0 F)
200730.6 C (87.1 F)
200830.6 C (87.1 F)
200930.6 C (87.1 F)
201029.4 C (84.9 F)
201128.3 C (82.9 F)
201230.6 C (87.1 F)
201330.0 C (86.0 F)
201428.9 C (84.0 F)
201530.0 C (86.0 F)
201629.4 C (84.9 F)
201729.4 C (84.9 F)
201830.6 C (87.1 F)
201928.3 C (82.9 F)
202029.4 C (84.9 F)
202130.0 C (86.0 F)
202229.4 C (84.9 F)
202330.6 C (87.1 F)
202430.0 C (86.0 F)
202530.6 C (87.1 F)
202632.2 C (90.0 F)

Coldest night (TNn)

Coldest night (TNn) at Aspen 1SW by year The coldest night of the year at Aspen 1SW, 1980 to 2026. The record is -31.7 C (-25.1 F) in 1989, marked on the chart; the median year is -23.9 C (-11.0 F). -35-30-25-20-1519801990200020102020Record: -31.7 C (-25.1 F) in 1989
The coldest night of the year at Aspen 1SW, 1980 to 2026. The record is -31.7 C (-25.1 F) in 1989, marked on the chart; the median year is -23.9 C (-11.0 F).
Coldest night (TNn) at Aspen 1SW by year
YearColdest night (TNn)
1980-19.4 C (-2.9 F)
1981-22.2 C (-8.0 F)
1982-28.9 C (-20.0 F)
1983-21.7 C (-7.1 F)
1984-26.1 C (-15.0 F)
1985-31.1 C (-24.0 F)
1986-24.4 C (-11.9 F)
1987-24.4 C (-11.9 F)
1988-26.7 C (-16.1 F)
1989-31.7 C (-25.1 F)
1990-29.4 C (-20.9 F)
1991-21.1 C (-6.0 F)
1992-23.9 C (-11.0 F)
1993-25.6 C (-14.1 F)
1994-25.0 C (-13.0 F)
1995-22.2 C (-8.0 F)
1996-30.6 C (-23.1 F)
1997-21.7 C (-7.1 F)
1998-26.1 C (-15.0 F)
1999-21.7 C (-7.1 F)
2000-20.0 C (-4.0 F)
2001-21.1 C (-6.0 F)
2002-26.1 C (-15.0 F)
2003-21.7 C (-7.1 F)
2004-24.4 C (-11.9 F)
2005-26.1 C (-15.0 F)
2006-23.9 C (-11.0 F)
2007-24.4 C (-11.9 F)
2008-23.9 C (-11.0 F)
2009-22.8 C (-9.0 F)
2010-25.0 C (-13.0 F)
2011-30.0 C (-22.0 F)
2012-24.4 C (-11.9 F)
2013-25.6 C (-14.1 F)
2014-22.2 C (-8.0 F)
2015-22.8 C (-9.0 F)
2016-23.9 C (-11.0 F)
2017-21.7 C (-7.1 F)
2018-19.4 C (-2.9 F)
2019-23.3 C (-9.9 F)
2020-23.9 C (-11.0 F)
2021-19.4 C (-2.9 F)
2022-23.3 C (-9.9 F)
2023-22.8 C (-9.0 F)
2024-20.6 C (-5.1 F)
2025-26.1 C (-15.0 F)
2026-22.2 C (-8.0 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Aspen 1SW by year The wettest day of the year at Aspen 1SW, 1980 to 2026. The record is 59.7 mm (2.4 in) in 1984, marked on the chart; the median year is 28.4 mm (1.1 in). 020406019801990200020102020Record: 59.7 mm (2.4 in) in 1984
The wettest day of the year at Aspen 1SW, 1980 to 2026. The record is 59.7 mm (2.4 in) in 1984, marked on the chart; the median year is 28.4 mm (1.1 in).
Wettest day (Rx1day) at Aspen 1SW by year
YearWettest day (Rx1day)
198015.2 mm (0.6 in)
198126.7 mm (1.1 in)
198227.9 mm (1.1 in)
198333.0 mm (1.3 in)
198459.7 mm (2.4 in)
198533.0 mm (1.3 in)
198623.6 mm (0.9 in)
198725.4 mm (1.0 in)
198845.7 mm (1.8 in)
198931.8 mm (1.3 in)
199021.8 mm (0.9 in)
199124.1 mm (0.9 in)
199228.4 mm (1.1 in)
199340.6 mm (1.6 in)
199422.9 mm (0.9 in)
199539.6 mm (1.6 in)
199648.8 mm (1.9 in)
199721.1 mm (0.8 in)
199825.4 mm (1.0 in)
199924.6 mm (1.0 in)
200023.6 mm (0.9 in)
200133.0 mm (1.3 in)
200223.4 mm (0.9 in)
200319.1 mm (0.8 in)
200427.9 mm (1.1 in)
200530.5 mm (1.2 in)
200621.6 mm (0.9 in)
200729.7 mm (1.2 in)
200829.2 mm (1.1 in)
200920.3 mm (0.8 in)
201033.8 mm (1.3 in)
201126.9 mm (1.1 in)
201222.9 mm (0.9 in)
201326.7 mm (1.1 in)
201455.9 mm (2.2 in)
201522.1 mm (0.9 in)
201637.6 mm (1.5 in)
201728.7 mm (1.1 in)
201835.8 mm (1.4 in)
201934.8 mm (1.4 in)
202030.5 mm (1.2 in)
202133.0 mm (1.3 in)
202233.0 mm (1.3 in)
202337.6 mm (1.5 in)
202431.0 mm (1.2 in)
202516.3 mm (0.6 in)
202617.5 mm (0.7 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Aspen 1SW by year The wettest five days of the year at Aspen 1SW, 1980 to 2026. The record is 91.4 mm (3.6 in) in 1984, marked on the chart; the median year is 52.1 mm (2.1 in). 2040608010019801990200020102020Record: 91.4 mm (3.6 in) in 1984
The wettest five days of the year at Aspen 1SW, 1980 to 2026. The record is 91.4 mm (3.6 in) in 1984, marked on the chart; the median year is 52.1 mm (2.1 in).
Wettest five days (Rx5day) at Aspen 1SW by year
YearWettest five days (Rx5day)
198036.3 mm (1.4 in)
198139.6 mm (1.6 in)
198254.7 mm (2.2 in)
198373.6 mm (2.9 in)
198491.4 mm (3.6 in)
198559.7 mm (2.4 in)
198629.2 mm (1.1 in)
198745.7 mm (1.8 in)
198853.8 mm (2.1 in)
198964.8 mm (2.6 in)
199047.0 mm (1.9 in)
199145.8 mm (1.8 in)
199251.6 mm (2.0 in)
199361.1 mm (2.4 in)
199452.7 mm (2.1 in)
199588.9 mm (3.5 in)
199686.4 mm (3.4 in)
199738.0 mm (1.5 in)
199842.4 mm (1.7 in)
199956.7 mm (2.2 in)
200037.3 mm (1.5 in)
200157.9 mm (2.3 in)
200239.2 mm (1.5 in)
200363.6 mm (2.5 in)
200443.1 mm (1.7 in)
200559.4 mm (2.3 in)
200644.3 mm (1.7 in)
200758.4 mm (2.3 in)
200859.9 mm (2.4 in)
200936.7 mm (1.4 in)
201046.5 mm (1.8 in)
201154.8 mm (2.2 in)
201231.6 mm (1.2 in)
201357.9 mm (2.3 in)
201482.3 mm (3.2 in)
201550.0 mm (2.0 in)
201665.1 mm (2.6 in)
201750.5 mm (2.0 in)
201844.2 mm (1.7 in)
201966.6 mm (2.6 in)
202035.1 mm (1.4 in)
202160.8 mm (2.4 in)
202264.3 mm (2.5 in)
202352.1 mm (2.1 in)
202449.1 mm (1.9 in)
202530.5 mm (1.2 in)
202631.0 mm (1.2 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Aspen 1SW by year The longest dry spell of the year at Aspen 1SW, 1980 to 2026. The record is 51 days in 2002, marked on the chart; the median year is 23 days. 10203040506019801990200020102020Record: 51 days in 2002
The longest dry spell of the year at Aspen 1SW, 1980 to 2026. The record is 51 days in 2002, marked on the chart; the median year is 23 days.
Longest dry spell (CDD) at Aspen 1SW by year
YearLongest dry spell (CDD)
198022 days
198123 days
198217 days
198321 days
198420 days
198518 days
198623 days
198725 days
198827 days
198928 days
199020 days
199137 days
199224 days
199319 days
199418 days
199520 days
199617 days
199741 days
199817 days
199919 days
200022 days
200120 days
200251 days
200328 days
200421 days
200517 days
200622 days
200729 days
200823 days
200917 days
201023 days
201122 days
201224 days
201317 days
201428 days
201516 days
201613 days
201733 days
201826 days
201925 days
202033 days
202131 days
202219 days
202331 days
202425 days
202526 days
202636 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 Aspen 1SW falls on 3 June and the median first autumn frost on 20 September, which leaves a median of 110 days between them.

Fitted over all years, the growing season changes by +8.3 days per decade at this station.

Frost dates and growing season at Aspen 1SW
MeasureMedian, all yearsEarliest periodRecent period (1989 to 2025)Recent against earliestFitted trend
Last spring frost3 Junen/a1 Junen/a-4.1 days per decade
First autumn frost20 Septembern/a22 Septembern/a+4.2 days per decade
Growing days110 daysn/a114 daysn/a+8.3 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

43 years, 1981 to 2025

A day with at least 28.4 mm (1.1 in) of rain is expected about once in 2 years. A day with at least 62.8 mm (2.5 in) of rain is expected about once in 100 years.

Rainfall return levels at Aspen 1SW: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years28.4 mm (1.1 in)
5 years36.2 mm (1.4 in)
10 years41.9 mm (1.6 in)
25 years49.7 mm (2.0 in)
50 years56.0 mm (2.2 in)Longer than the 43 years of record
100 years62.8 mm (2.5 in)Longer than the 43 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, 43 years of values from 1981 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: 59.7 mm (2.4 in) in 1984; 55.9 mm (2.2 in) in 2014; 48.8 mm (1.9 in) in 1996.

Download the Data

  • Data for Aspen 1SW standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Aspen 1SW 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-14).