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Arco Idaho Weather Records (USR0000IARC)

Record envelope, standing records and threshold days for Arco Idaho (USR0000IARC), Idaho, United States, with 38 years of record.

Key Facts for Arco Idaho

  • Arco Idaho (USR0000IARC) is a weather station in Idaho, United States at 43.62 latitude and -113.39 longitude, 1,640 m (5,380 ft) above sea level.
  • The station reports from 1986 to 2023, 38 years of record.
  • 1,464 records set at Arco Idaho still stand.
  • Records are tracked for tmax, tmin: an element needs 30 years of data to be eligible.
  • Arco Idaho set a daily record high maximum temperature of 27.8 C (82.0 F) on 8 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, 43.62 latitude, -113.39 longitude.
  • Elevation: 1,640 m (5,380 ft).
  • Period of record: 1986 to 2023, 38 years.
  • Eligible elements: tmax, tmin.

Daily Record Envelope and 2026

37 days at or beyond a record
Daily record high and record low at Arco Idaho, with 2026 drawn through them The band shows the record high and record low for each calendar day at Arco Idaho. The lines show the 2026 daily maximum and minimum. 37 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -60-40-200204060 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Arco Idaho. The lines show the 2026 daily maximum and minimum. 37 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Arco Idaho, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan11.7 C (53.1 F)-35.0 C (-31.0 F)8.9 C (48.0 F)-19.4 C (-2.9 F)
Feb15.0 C (59.0 F)-36.7 C (-34.1 F)13.9 C (57.0 F)-19.4 C (-2.9 F)
Mar25.6 C (78.1 F)-26.1 C (-15.0 F)25.6 C (78.1 F)-11.7 C (10.9 F)
Apr28.9 C (84.0 F)-16.1 C (3.0 F)23.3 C (73.9 F)-9.4 C (15.1 F)
May35.0 C (95.0 F)-11.1 C (12.0 F)30.6 C (87.1 F)-5.6 C (21.9 F)
Jun37.8 C (100.0 F)-6.7 C (19.9 F)33.3 C (91.9 F)-2.2 C (28.0 F)
Jul40.6 C (105.1 F)-1.1 C (30.0 F)37.2 C (99.0 F)7.2 C (45.0 F)
Aug38.3 C (100.9 F)-4.4 C (24.1 F)37.2 C (99.0 F)-0.6 C (30.9 F)
Sep36.7 C (98.1 F)-8.9 C (16.0 F)27.8 C (82.0 F)-1.7 C (28.9 F)
Oct32.2 C (90.0 F)-20.0 C (-4.0 F)30.0 C (86.0 F)1.7 C (35.1 F)
Nov20.6 C (69.1 F)-34.4 C (-29.9 F)n/an/a
Dec18.3 C (64.9 F)-42.2 C (-44.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Arco Idaho by the year they were set 1,464 records at Arco Idaho still stand. 2010 holds the most, with 97. 02550751001987: 391988: 431989: 481990: 541991: 491992: 501993: 601994: 321995: 421996: 441997: 181998: 261999: 282000: 302001: 312002: 462003: 432004: 162005: 132006: 382007: 262008: 442009: 342010: 972011: 312012: 332013: 402014: 302015: 332016: 252017: 302018: 252019: 292020: 252021: 352022: 382023: 322024: 232025: 412026: 431987199119951999200320072011201520192023
1,464 records at Arco Idaho still stand. 2010 holds the most, with 97.
Standing records at Arco Idaho by the year they were set
Year setStanding records
198739
198843
198948
199054
199149
199250
199360
199432
199542
199644
199718
199826
199928
200030
200131
200246
200343
200416
200513
200638
200726
200844
200934
201097
201131
201233
201340
201430
201533
201625
201730
201825
201929
202025
202135
202238
202332
202423
202541
202643

All-Time Record Progression

1 new records
When Arco Idaho set new all-time records 1 all-time records were set at Arco Idaho between 21 July 2026 and 21 July 2026. Each dot is a new record. Record high minimum temperature21 July 2026: Record high minimum temperature 21.7 C (71.1 F)
1 all-time records were set at Arco Idaho between 21 July 2026 and 21 July 2026. Each dot is a new record.
When Arco Idaho set new all-time records
DateKindDetail
2026-07-21Record high minimum temperatureRecord high minimum temperature 21.7 C (71.1 F)

Period of Record Coverage

1986 to 2026
Days with data per year at Arco Idaho 41 years of record at Arco Idaho, 1986 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1986, 2026. 1986: 49 of 365 days1987: 353 of 365 days1988: 363 of 366 days1989: 364 of 365 days1990: 361 of 365 days1991: 364 of 365 days1992: 366 of 366 days1993: 357 of 365 days1994: 362 of 365 days1995: 363 of 365 days1996: 365 of 366 days1997: 363 of 365 days1998: 365 of 365 days1999: 365 of 365 days2000: 366 of 366 days2001: 365 of 365 days2002: 365 of 365 days2003: 350 of 365 days2004: 366 of 366 days2005: 365 of 365 days2006: 365 of 365 days2007: 365 of 365 days2008: 366 of 366 days2009: 364 of 365 days2010: 365 of 365 days2011: 365 of 365 days2012: 366 of 366 days2013: 364 of 365 days2014: 363 of 365 days2015: 365 of 365 days2016: 364 of 366 days2017: 359 of 365 days2018: 365 of 365 days2019: 355 of 365 days2020: 366 of 366 days2021: 364 of 365 days2022: 365 of 365 days2023: 365 of 365 days2024: 366 of 366 days2025: 365 of 365 days2026: 283 of 365 days1990200020102020
41 years of record at Arco Idaho, 1986 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1986, 2026.
Days with data per year at Arco Idaho
YearDays with dataShare of yearComplete
19864913%No
198735397%Yes
198836399%Yes
1989364100%Yes
199036199%Yes
1991364100%Yes
1992366100%Yes
199335798%Yes
199436299%Yes
199536399%Yes
1996365100%Yes
199736399%Yes
1998365100%Yes
1999365100%Yes
2000366100%Yes
2001365100%Yes
2002365100%Yes
200335096%Yes
2004366100%Yes
2005365100%Yes
2006365100%Yes
2007365100%Yes
2008366100%Yes
2009364100%Yes
2010365100%Yes
2011365100%Yes
2012366100%Yes
2013364100%Yes
201436399%Yes
2015365100%Yes
201636499%Yes
201735998%Yes
2018365100%Yes
201935597%Yes
2020366100%Yes
2021364100%Yes
2022365100%Yes
2023365100%Yes
2024366100%Yes
2025365100%Yes
202628378%No

Latest Records

20
Latest records at Arco Idaho
DateStationRecordValueBeat old record byOld record stoodSignificance
8 October 2026Arco Idaho, USdaily high max (Provisional)27.8 C (82.0 F)1.1 C (2.0 F)37 years16 of 100 (Routine)
7 October 2026Arco Idaho, USdaily high max (Provisional)28.3 C (82.9 F)2.7 C (4.9 F)29 years16 of 100 (Routine)
6 October 2026Arco Idaho, USdaily high max (Provisional)28.3 C (82.9 F)2.2 C (4.0 F)29 years15 of 100 (Routine)
5 October 2026Arco Idaho, USdaily high max (Provisional)30.0 C (86.0 F)2.8 C (5.0 F)37 years19 of 100 (Routine)
5 October 2026Arco Idaho, USdaily high min (Provisional)8.3 C (46.9 F)1.1 C (2.0 F)16 years10 of 100 (Routine)
4 October 2026Arco Idaho, USdaily high max (Provisional)29.4 C (84.9 F)1.6 C (2.9 F)32 years15 of 100 (Routine)
8 September 2026Arco Idaho, USdaily low min (Tie, Provisional)-1.7 C (28.9 F)tie24 years2 of 100 (Routine)
31 August 2026Arco Idaho, USdaily low min (Provisional)-0.6 C (30.9 F)0.6 C (1.1 F)27 years13 of 100 (Routine)
28 August 2026Arco Idaho, USdaily high min (Provisional)15.6 C (60.1 F)4.5 C (8.1 F)24 years24 of 100 (Routine)
22 August 2026Arco Idaho, USdaily high min (Provisional)16.1 C (61.0 F)1.1 C (2.0 F)16 years12 of 100 (Routine)
21 August 2026Arco Idaho, USdaily high min (Provisional)16.7 C (62.1 F)1.1 C (2.0 F)23 years13 of 100 (Routine)
21 August 2026Arco Idaho, USdaily high max (Tie, Provisional)37.2 C (99.0 F)tie16 years2 of 100 (Routine)
20 August 2026Arco Idaho, USdaily high max (Provisional)36.1 C (97.0 F)1.1 C (2.0 F)23 years12 of 100 (Routine)
13 August 2026Arco Idaho, USdaily low max (Tie)22.2 C (72.0 F)tie39 years3 of 100 (Routine)
12 August 2026Arco Idaho, USmonthly high min (Tie)18.3 C (64.9 F)tie22 years5 of 100 (Routine)
4 August 2026Arco Idaho, USdaily low min2.8 C (37.0 F)0.5 C (0.9 F)29 years13 of 100 (Routine)
26 July 2026Arco Idaho, USdaily high min (Tie)15.0 C (59.0 F)tie12 years1 of 100 (Routine)
25 July 2026Arco Idaho, USdaily high max36.7 C (98.1 F)0.6 C (1.1 F)17 years10 of 100 (Routine)
24 July 2026Arco Idaho, USdaily high max37.2 C (99.0 F)1.6 C (2.9 F)24 years15 of 100 (Routine)
21 July 2026Arco Idaho, USall-time high min21.7 C (71.1 F)0.6 C (1.1 F)19 years30 of 100 (Routine)

Climate Trend

38 complete years, 1987 to 2025
Annual mean temperature at Arco Idaho as warming stripes, 1987 to 2025 One stripe for each of 38 complete years at Arco Idaho, 1987 to 2025. Blue stripes are years cooler than the station's own mean of 5.9 C (42.7 F); red stripes are warmer. The coolest year was 1993, at 3.5 C (38.2 F), and the warmest was 2010, at 7.7 C (45.9 F). The strongest colour marks a difference of 2.5 C (4.5 F). 1987: 6.4 C, +0.5 C from the station mean1988: 6.1 C, +0.2 C from the station mean1989: 4.6 C, -1.3 C from the station mean1990: 5.6 C, -0.3 C from the station mean1991: 6.6 C, +0.7 C from the station mean1992: 6.9 C, +0.9 C from the station mean1993: 3.5 C, -2.5 C from the station mean1994: 6.0 C, +0.1 C from the station mean1995: 5.7 C, -0.2 C from the station mean1996: 5.9 C, 0.0 C from the station mean1997: 5.6 C, -0.3 C from the station mean1998: 5.9 C, 0.0 C from the station mean1999: 5.7 C, -0.3 C from the station mean2000: 6.3 C, +0.4 C from the station mean2001: 5.8 C, -0.1 C from the station mean2002: 5.1 C, -0.8 C from the station mean2004: 6.1 C, +0.2 C from the station mean2005: 5.4 C, -0.5 C from the station mean2006: 5.8 C, -0.2 C from the station mean2007: 6.8 C, +0.9 C from the station mean2008: 4.7 C, -1.2 C from the station mean2009: 5.3 C, -0.6 C from the station mean2010: 7.7 C, +1.8 C from the station mean2011: 4.6 C, -1.3 C from the station mean2012: 7.0 C, +1.1 C from the station mean2013: 5.9 C, 0.0 C from the station mean2014: 7.1 C, +1.2 C from the station mean2015: 7.3 C, +1.4 C from the station mean2016: 6.0 C, +0.1 C from the station mean2017: 6.0 C, +0.1 C from the station mean2018: 6.3 C, +0.4 C from the station mean2019: 4.9 C, -1.1 C from the station mean2020: 5.7 C, -0.2 C from the station mean2021: 6.6 C, +0.6 C from the station mean2022: 4.8 C, -1.2 C from the station mean2023: 5.1 C, -0.8 C from the station mean2024: 6.7 C, +0.8 C from the station mean2025: 7.4 C, +1.5 C from the station mean198719901995200020052010201520202025
One stripe for each of 38 complete years at Arco Idaho, 1987 to 2025. Blue stripes are years cooler than the station's own mean of 5.9 C (42.7 F); red stripes are warmer. The coolest year was 1993, at 3.5 C (38.2 F), and the warmest was 2010, at 7.7 C (45.9 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Arco Idaho as warming stripes, 1987 to 2025
YearAnnual mean temperatureDifference from the station mean
19876.4 C+0.52 C
19886.1 C+0.21 C
19894.6 C-1.35 C
19905.6 C-0.32 C
19916.6 C+0.66 C
19926.9 C+0.94 C
19933.5 C-2.47 C
19946.0 C+0.12 C
19955.7 C-0.22 C
19965.9 C-0.01 C
19975.6 C-0.34 C
19985.9 C+0.02 C
19995.7 C-0.26 C
20006.3 C+0.37 C
20015.8 C-0.08 C
20025.1 C-0.80 C
20046.1 C+0.20 C
20055.4 C-0.51 C
20065.8 C-0.16 C
20076.8 C+0.89 C
20084.7 C-1.21 C
20095.3 C-0.64 C
20107.7 C+1.81 C
20114.6 C-1.29 C
20127.0 C+1.06 C
20135.9 C-0.02 C
20147.1 C+1.20 C
20157.3 C+1.42 C
20166.0 C+0.11 C
20176.0 C+0.05 C
20186.3 C+0.39 C
20194.9 C-1.07 C
20205.7 C-0.19 C
20216.6 C+0.63 C
20224.8 C-1.17 C
20235.1 C-0.82 C
20246.7 C+0.81 C
20257.4 C+1.50 C

The fitted trend in annual mean temperature here over 1987 to 2025 is 0.1 C (-0.1 to 0.4) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.2 F (-0.2 to 0.7) per decade. The slope is a straight line fitted to 38 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Arco Idaho
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.1 C (-0.1 to 0.4) per decade0.2 F (-0.2 to 0.7) per decade1987 to 202538Not clearly different from zero
Mean daily maximum0.1 C (-0.2 to 0.3) per decade0.1 F (-0.3 to 0.6) per decade1987 to 202538Not clearly different from zero
Mean daily minimum0.2 C (-0.1 to 0.5) per decade0.3 F (-0.2 to 0.9) per decade1987 to 202538Not clearly different from zero

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

1986 to 2026
Yearly extremes at Arco Idaho: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)40.6 C (105.1 F)200236.7 C (98.1 F)41
Coldest night (TNn)-42.2 C (-44.0 F)1990-31.0 C (-23.8 F)41

Hottest day (TXx)

Hottest day (TXx) at Arco Idaho by year The hottest day of the year at Arco Idaho, 1986 to 2026. The record is 40.6 C (105.1 F) in 2002, marked on the chart; the median year is 36.7 C (98.1 F). 10203040501990200020102020Record: 40.6 C (105.1 F) in 2002
The hottest day of the year at Arco Idaho, 1986 to 2026. The record is 40.6 C (105.1 F) in 2002, marked on the chart; the median year is 36.7 C (98.1 F).
Hottest day (TXx) at Arco Idaho by year
YearHottest day (TXx)
198610.0 C (50.0 F)
198733.3 C (91.9 F)
198836.7 C (98.1 F)
198936.1 C (97.0 F)
199037.2 C (99.0 F)
199135.6 C (96.1 F)
199236.1 C (97.0 F)
199330.6 C (87.1 F)
199436.7 C (98.1 F)
199533.9 C (93.0 F)
199636.1 C (97.0 F)
199734.4 C (93.9 F)
199837.2 C (99.0 F)
199935.6 C (96.1 F)
200038.9 C (102.0 F)
200137.8 C (100.0 F)
200240.6 C (105.1 F)
200338.9 C (102.0 F)
200436.1 C (97.0 F)
200536.7 C (98.1 F)
200639.4 C (102.9 F)
200738.9 C (102.0 F)
200836.1 C (97.0 F)
200937.2 C (99.0 F)
201035.6 C (96.1 F)
201136.1 C (97.0 F)
201236.1 C (97.0 F)
201337.8 C (100.0 F)
201435.6 C (96.1 F)
201537.2 C (99.0 F)
201635.6 C (96.1 F)
201736.7 C (98.1 F)
201837.8 C (100.0 F)
201936.1 C (97.0 F)
202037.2 C (99.0 F)
202137.2 C (99.0 F)
202236.7 C (98.1 F)
202336.7 C (98.1 F)
202437.2 C (99.0 F)
202535.6 C (96.1 F)
202637.2 C (99.0 F)

Coldest night (TNn)

Coldest night (TNn) at Arco Idaho by year The coldest night of the year at Arco Idaho, 1986 to 2026. The record is -42.2 C (-44.0 F) in 1990, marked on the chart; the median year is -31.0 C (-23.8 F). -50-40-30-20-101990200020102020Record: -42.2 C (-44.0 F) in 1990
The coldest night of the year at Arco Idaho, 1986 to 2026. The record is -42.2 C (-44.0 F) in 1990, marked on the chart; the median year is -31.0 C (-23.8 F).
Coldest night (TNn) at Arco Idaho by year
YearColdest night (TNn)
1986-21.1 C (-6.0 F)
1987-27.2 C (-17.0 F)
1988-36.1 C (-33.0 F)
1989-33.3 C (-27.9 F)
1990-42.2 C (-44.0 F)
1991-27.8 C (-18.0 F)
1992-31.7 C (-25.1 F)
1993-32.2 C (-26.0 F)
1994-26.1 C (-15.0 F)
1995-26.7 C (-16.1 F)
1996-36.7 C (-34.1 F)
1997-27.2 C (-17.0 F)
1998-33.9 C (-29.0 F)
1999-22.2 C (-8.0 F)
2000-22.2 C (-8.0 F)
2001-30.0 C (-22.0 F)
2002-31.1 C (-24.0 F)
2003-21.7 C (-7.1 F)
2004-31.7 C (-25.1 F)
2005-33.3 C (-27.9 F)
2006-30.6 C (-23.1 F)
2007-27.8 C (-18.0 F)
2008-30.0 C (-22.0 F)
2009-33.9 C (-29.0 F)
2010-34.4 C (-29.9 F)
2011-32.8 C (-27.0 F)
2012-25.6 C (-14.1 F)
2013-35.0 C (-31.0 F)
2014-30.6 C (-23.1 F)
2015-32.8 C (-27.0 F)
2016-34.4 C (-29.9 F)
2017-33.3 C (-27.9 F)
2018-24.4 C (-11.9 F)
2019-25.6 C (-14.1 F)
2020-22.8 C (-9.0 F)
2021-27.8 C (-18.0 F)
2022-31.7 C (-25.1 F)
2023-34.4 C (-29.9 F)
2024-33.0 C (-27.4 F)
2025-31.0 C (-23.8 F)
2026-19.4 C (-2.9 F)

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

38 years with a frost

Across 38 years with a frost, the median last spring frost at Arco Idaho falls on 15 June and the median first autumn frost on 9 September, which leaves a median of 87 days between them.

Fitted over all years, the growing season changes by +1.6 days per decade at this station.

Frost dates and growing season at Arco Idaho
MeasureMedian, all yearsEarliest periodRecent period (1995 to 2025)Recent against earliestFitted trend
Last spring frost15 Junen/a15 Junen/a+1.3 days per decade
First autumn frost9 Septembern/a9 Septembern/a+2.9 days per decade
Growing days87 daysn/a87 daysn/a+1.6 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.

Download the Data

  • Data for Arco Idaho standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Arco Idaho 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-13).