Built 2026-10-19 (19 October 2026)

Bortnan_A Weather Records (SWE00139888)

Record envelope, standing records and threshold days for Bortnan_A (SWE00139888), Sweden, with 32 years of record.

Key Facts for Bortnan_A

  • Bortnan_A (SWE00139888) is a weather station in Sweden at 62.76 latitude and 13.85 longitude, 467 m (1,532 ft) above sea level.
  • The station reports from 1995 to 2026, 32 years of record.
  • 1,464 records set at Bortnan_A still stand.
  • Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
  • Bortnan_A set a daily record precipitation of 16.0 mm (0.6 in) on 6 August 2026.

About the Station

  • Location: Sweden, 62.76 latitude, 13.85 longitude.
  • Elevation: 467 m (1,532 ft).
  • Period of record: 1995 to 2026, 32 years.
  • Eligible elements: tmax, tmin, prcp.

Daily Record Envelope and 2026

13 days at or beyond a record
Daily record high and record low at Bortnan_A, with 2026 drawn through them The band shows the record high and record low for each calendar day at Bortnan_A. The lines show the 2026 daily maximum and minimum. 13 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -60-40-2002040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Bortnan_A. The lines show the 2026 daily maximum and minimum. 13 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Bortnan_A, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan9.6 C (49.3 F)-39.0 C (-38.2 F)1.8 C (35.2 F)-35.1 C (-31.2 F)
Feb10.3 C (50.5 F)-40.1 C (-40.2 F)6.4 C (43.5 F)-34.2 C (-29.6 F)
Mar14.2 C (57.6 F)-34.4 C (-29.9 F)10.4 C (50.7 F)-21.4 C (-6.5 F)
Apr19.4 C (66.9 F)-23.2 C (-9.8 F)15.6 C (60.1 F)-12.5 C (9.5 F)
May28.1 C (82.6 F)-10.7 C (12.7 F)21.7 C (71.1 F)-8.4 C (16.9 F)
Jun29.4 C (84.9 F)-6.3 C (20.7 F)24.8 C (76.6 F)-0.7 C (30.7 F)
Jul30.3 C (86.5 F)-2.5 C (27.5 F)30.3 C (86.5 F)-0.8 C (30.6 F)
Aug27.6 C (81.7 F)-4.5 C (23.9 F)22.7 C (72.9 F)-0.6 C (30.9 F)
Sep25.8 C (78.4 F)-9.9 C (14.2 F)n/an/a
Oct20.1 C (68.2 F)-20.8 C (-5.4 F)n/an/a
Nov12.3 C (54.1 F)-30.3 C (-22.5 F)n/an/a
Dec8.7 C (47.7 F)-35.0 C (-31.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Bortnan_A by the year they were set 1,464 records at Bortnan_A still stand. 2010 holds the most, with 75. 0204060801995: 11996: 481997: 491998: 391999: 552000: 502001: 662002: 682003: 342004: 412005: 522006: 622007: 472008: 342009: 442010: 752011: 432012: 412013: 372014: 502015: 292016: 472017: 242018: 532019: 632020: 412021: 362022: 342023: 602024: 572025: 612026: 2319951999200320072011201520192023
1,464 records at Bortnan_A still stand. 2010 holds the most, with 75.
Standing records at Bortnan_A by the year they were set
Year setStanding records
19951
199648
199749
199839
199955
200050
200166
200268
200334
200441
200552
200662
200747
200834
200944
201075
201143
201241
201337
201450
201529
201647
201724
201853
201963
202041
202136
202234
202360
202457
202561
202623

All-Time Record Progression

1 new records
When Bortnan_A set new all-time records 1 all-time records were set at Bortnan_A between 16 July 2026 and 16 July 2026. Each dot is a new record. Record high maximum temperature16 July 2026: Record high maximum temperature 30.3 C (86.5 F)
1 all-time records were set at Bortnan_A between 16 July 2026 and 16 July 2026. Each dot is a new record.
When Bortnan_A set new all-time records
DateKindDetail
2026-07-16Record high maximum temperatureRecord high maximum temperature 30.3 C (86.5 F)

Wettest Day of Each Month

Jun: 66.0 mm (2.6 in)
Record daily precipitation for each month at Bortnan_A The wettest day on record for each calendar month at Bortnan_A. The most was 66.0 mm (2.6 in) on 30 June 2023. 020406080 Jan: 14.1 mm (0.6 in), 21 January 2021 Jan Feb: 11.1 mm (0.4 in), 10 February 2011 Feb Mar: 13.3 mm (0.5 in), 17 March 2019 Mar Apr: 17.8 mm (0.7 in), 27 April 2002 Apr May: 27.0 mm (1.1 in), 26 May 2009 May Jun: 66.0 mm (2.6 in), 30 June 2023 Jun Jul: 43.7 mm (1.7 in), 5 July 1998 Jul Aug: 43.4 mm (1.7 in), 19 August 2017 Aug Sep: 37.6 mm (1.5 in), 22 September 2003 Sep Oct: 22.0 mm (0.9 in), 12 October 2000 Oct Nov: 23.5 mm (0.9 in), 18 November 2020 Nov Dec: 17.0 mm (0.7 in), 13 December 2000 Dec
The wettest day on record for each calendar month at Bortnan_A. The most was 66.0 mm (2.6 in) on 30 June 2023.
Record daily precipitation for each month at Bortnan_A
MonthRecord daily precipitation (mm)Date
Jan14.1 mm (0.6 in)21 January 2021
Feb11.1 mm (0.4 in)10 February 2011
Mar13.3 mm (0.5 in)17 March 2019
Apr17.8 mm (0.7 in)27 April 2002
May27.0 mm (1.1 in)26 May 2009
Jun66.0 mm (2.6 in)30 June 2023
Jul43.7 mm (1.7 in)5 July 1998
Aug43.4 mm (1.7 in)19 August 2017
Sep37.6 mm (1.5 in)22 September 2003
Oct22.0 mm (0.9 in)12 October 2000
Nov23.5 mm (0.9 in)18 November 2020
Dec17.0 mm (0.7 in)13 December 2000

Period of Record Coverage

1995 to 2026
Days with data per year at Bortnan_A 32 years of record at Bortnan_A, 1995 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1995, 2026. 1995: 17 of 365 days1996: 366 of 366 days1997: 365 of 365 days1998: 365 of 365 days1999: 365 of 365 days2000: 366 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: 365 of 365 days2026: 242 of 365 days1995200020052010201520202025
32 years of record at Bortnan_A, 1995 to 2026. 2 years have data for under 90 percent of days and are left out of rankings: 1995, 2026.
Days with data per year at Bortnan_A
YearDays with dataShare of yearComplete
1995175%No
1996366100%Yes
1997365100%Yes
1998365100%Yes
1999365100%Yes
2000366100%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
2025365100%Yes
202624266%No

Latest Records

20
Latest records at Bortnan_A
DateStationRecordValueBeat old record byOld record stoodSignificance
6 August 2026Bortnan_A, SEdaily rain16.0 mm (0.6 in)3.0 mm (0.12 in)3 years8 of 100 (Routine)
30 July 2026Bortnan_A, SEdaily rain30.2 mm (1.2 in)9.5 mm (0.37 in)13 years22 of 100 (Routine)
20 July 2026Bortnan_A, SEdaily low min-0.8 C (30.6 F)0.2 C (0.4 F)20 years9 of 100 (Routine)
16 July 2026Bortnan_A, SEall-time high max30.3 C (86.5 F)0.4 C (0.7 F)6 years25 of 100 (Routine)
12 July 2026Bortnan_A, SEdaily low min2.0 C (35.6 F)0.3 C (0.5 F)19 years8 of 100 (Routine)
6 June 2026Bortnan_A, SEdaily rain19.5 mm (0.8 in)7.2 mm (0.28 in)11 years17 of 100 (Routine)
4 June 2026Bortnan_A, SEdaily high min10.0 C (50.0 F)0.8 C (1.4 F)23 years11 of 100 (Routine)
1 June 2026Bortnan_A, SEdaily rain (Tie)7.5 mm (0.30 in)tie1 year0 of 100 (Routine)
30 May 2026Bortnan_A, SEdaily high min10.0 C (50.0 F)0.2 C (0.4 F)19 years8 of 100 (Routine)
10 May 2026Bortnan_A, SEdaily rain (Tie)7.9 mm (0.31 in)tie16 years1 of 100 (Routine)
24 April 2026Bortnan_A, SEdaily high min2.9 C (37.2 F)0.8 C (1.4 F)5 years5 of 100 (Routine)
1 April 2026Bortnan_A, SEdaily high max11.8 C (53.2 F)1.6 C (2.9 F)20 years12 of 100 (Routine)
30 March 2026Bortnan_A, SEdaily rain3.5 mm (0.14 in)1.0 mm (0.04 in)20 years14 of 100 (Routine)
21 March 2026Bortnan_A, SEdaily high max10.4 C (50.7 F)1.4 C (2.5 F)15 years10 of 100 (Routine)
18 March 2026Bortnan_A, SEdaily high max7.9 C (46.2 F)0.4 C (0.7 F)21 years9 of 100 (Routine)
13 March 2026Bortnan_A, SEdaily high min2.0 C (35.6 F)2.8 C (5.0 F)12 years9 of 100 (Routine)
5 March 2026Bortnan_A, SEdaily high max6.4 C (43.5 F)1.6 C (2.9 F)28 years14 of 100 (Routine)
4 March 2026Bortnan_A, SEdaily high min-0.1 C (31.8 F)0.2 C (0.4 F)1 year3 of 100 (Routine)
14 February 2026Bortnan_A, SEdaily low min-30.7 C (-23.3 F)3.4 C (6.1 F)28 years14 of 100 (Routine)
13 February 2026Bortnan_A, SEdaily low min-32.3 C (-26.1 F)2.6 C (4.7 F)15 years9 of 100 (Routine)

Climate Trend

30 complete years, 1996 to 2025
Annual mean temperature at Bortnan_A as warming stripes, 1996 to 2025 One stripe for each of 30 complete years at Bortnan_A, 1996 to 2025. Blue stripes are years cooler than the station's own mean of 1.6 C (34.9 F); red stripes are warmer. The coolest year was 2010, at -1.1 C (30.0 F), and the warmest was 2025, at 3.6 C (38.4 F). The strongest colour marks a difference of 2.8 C (5.0 F). 1996: -0.3 C, -2.0 C from the station mean1997: 1.7 C, 0.0 C from the station mean1998: 1.1 C, -0.5 C from the station mean1999: 1.3 C, -0.4 C from the station mean2000: 2.2 C, +0.6 C from the station mean2001: 0.7 C, -1.0 C from the station mean2002: 1.3 C, -0.4 C from the station mean2003: 1.7 C, +0.1 C from the station mean2004: 1.6 C, -0.1 C from the station mean2005: 1.9 C, +0.3 C from the station mean2006: 2.3 C, +0.7 C from the station mean2007: 1.5 C, -0.1 C from the station mean2008: 1.7 C, +0.1 C from the station mean2009: 0.9 C, -0.7 C from the station mean2010: -1.1 C, -2.8 C from the station mean2011: 2.7 C, +1.0 C from the station mean2012: 0.8 C, -0.8 C from the station mean2013: 1.4 C, -0.2 C from the station mean2014: 2.7 C, +1.0 C from the station mean2015: 2.3 C, +0.7 C from the station mean2016: 1.7 C, +0.1 C from the station mean2017: 1.5 C, -0.1 C from the station mean2018: 1.6 C, 0.0 C from the station mean2019: 1.9 C, +0.2 C from the station mean2020: 3.3 C, +1.7 C from the station mean2021: 1.3 C, -0.3 C from the station mean2022: 2.4 C, +0.7 C from the station mean2023: 0.8 C, -0.8 C from the station mean2024: 2.7 C, +1.1 C from the station mean2025: 3.6 C, +1.9 C from the station mean1996200020052010201520202025
One stripe for each of 30 complete years at Bortnan_A, 1996 to 2025. Blue stripes are years cooler than the station's own mean of 1.6 C (34.9 F); red stripes are warmer. The coolest year was 2010, at -1.1 C (30.0 F), and the warmest was 2025, at 3.6 C (38.4 F). The strongest colour marks a difference of 2.8 C (5.0 F).
Annual mean temperature at Bortnan_A as warming stripes, 1996 to 2025
YearAnnual mean temperatureDifference from the station mean
1996-0.3 C-1.97 C
19971.7 C+0.04 C
19981.1 C-0.52 C
19991.3 C-0.35 C
20002.2 C+0.56 C
20010.7 C-0.96 C
20021.3 C-0.35 C
20031.7 C+0.06 C
20041.6 C-0.07 C
20051.9 C+0.27 C
20062.3 C+0.68 C
20071.5 C-0.14 C
20081.7 C+0.07 C
20090.9 C-0.70 C
2010-1.1 C-2.75 C
20112.7 C+1.04 C
20120.8 C-0.82 C
20131.4 C-0.21 C
20142.7 C+1.04 C
20152.3 C+0.68 C
20161.7 C+0.08 C
20171.5 C-0.13 C
20181.6 C-0.03 C
20191.9 C+0.25 C
20203.3 C+1.67 C
20211.3 C-0.32 C
20222.4 C+0.74 C
20230.8 C-0.79 C
20242.7 C+1.09 C
20253.6 C+1.92 C

The annual mean temperature here has risen by 0.5 C (0.1 to 0.8) per decade over 1996 to 2025. In Fahrenheit: 0.8 F (0.1 to 1.5) per decade. The slope is a straight line fitted to 30 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Bortnan_A
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.5 C (0.1 to 0.8) per decade0.8 F (0.1 to 1.5) per decade1996 to 202530Rise
Mean daily maximum0.38 C (-0.01 to 0.76) per decade0.68 F (-0.02 to 1.37) per decade1996 to 202530Not clearly different from zero
Mean daily minimum0.5 C (0.1 to 1.0) per decade1.0 F (0.2 to 1.7) per decade1996 to 202530Rise

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

1995 to 2026
Yearly extremes at Bortnan_A: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)30.3 C (86.5 F)202627.6 C (81.7 F)32
Coldest night (TNn)-40.1 C (-40.2 F)2001-32.9 C (-27.3 F)32
Wettest day (Rx1day)66.0 mm (2.6 in)202327.1 mm (1.1 in)32
Wettest five days (Rx5day)86.3 mm (3.4 in)202352.0 mm (2.0 in)32
Longest dry spell (CDD)55 days200325 days32

Hottest day (TXx)

Hottest day (TXx) at Bortnan_A by year The hottest day of the year at Bortnan_A, 1995 to 2026. The record is 30.3 C (86.5 F) in 2026, marked on the chart; the median year is 27.6 C (81.7 F). 010203040200020102020Record: 30.3 C (86.5 F) in 2026
The hottest day of the year at Bortnan_A, 1995 to 2026. The record is 30.3 C (86.5 F) in 2026, marked on the chart; the median year is 27.6 C (81.7 F).
Hottest day (TXx) at Bortnan_A by year
YearHottest day (TXx)
19954.4 C (39.9 F)
199625.5 C (77.9 F)
199725.7 C (78.3 F)
199823.8 C (74.8 F)
199928.1 C (82.6 F)
200023.9 C (75.0 F)
200127.9 C (82.2 F)
200225.8 C (78.4 F)
200329.7 C (85.5 F)
200427.3 C (81.1 F)
200527.6 C (81.7 F)
200629.4 C (84.9 F)
200727.6 C (81.7 F)
200828.7 C (83.7 F)
200927.2 C (81.0 F)
201024.8 C (76.6 F)
201126.9 C (80.4 F)
201224.3 C (75.7 F)
201326.4 C (79.5 F)
201428.3 C (82.9 F)
201529.3 C (84.7 F)
201625.6 C (78.1 F)
201723.4 C (74.1 F)
201829.3 C (84.7 F)
201929.9 C (85.8 F)
202029.3 C (84.7 F)
202127.7 C (81.9 F)
202228.2 C (82.8 F)
202326.3 C (79.3 F)
202428.5 C (83.3 F)
202529.3 C (84.7 F)
202630.3 C (86.5 F)

Coldest night (TNn)

Coldest night (TNn) at Bortnan_A by year The coldest night of the year at Bortnan_A, 1995 to 2026. The record is -40.1 C (-40.2 F) in 2001, marked on the chart; the median year is -32.9 C (-27.3 F). -45-40-35-30-25200020102020Record: -40.1 C (-40.2 F) in 2001
The coldest night of the year at Bortnan_A, 1995 to 2026. The record is -40.1 C (-40.2 F) in 2001, marked on the chart; the median year is -32.9 C (-27.3 F).
Coldest night (TNn) at Bortnan_A by year
YearColdest night (TNn)
1995-28.8 C (-19.8 F)
1996-31.9 C (-25.4 F)
1997-34.8 C (-30.6 F)
1998-29.2 C (-20.6 F)
1999-39.0 C (-38.2 F)
2000-31.7 C (-25.1 F)
2001-40.1 C (-40.2 F)
2002-34.0 C (-29.2 F)
2003-36.2 C (-33.2 F)
2004-34.0 C (-29.2 F)
2005-34.2 C (-29.6 F)
2006-31.1 C (-24.0 F)
2007-34.7 C (-30.5 F)
2008-32.1 C (-25.8 F)
2009-34.6 C (-30.3 F)
2010-37.4 C (-35.3 F)
2011-34.1 C (-29.4 F)
2012-37.2 C (-35.0 F)
2013-31.0 C (-23.8 F)
2014-32.0 C (-25.6 F)
2015-28.1 C (-18.6 F)
2016-33.3 C (-27.9 F)
2017-32.6 C (-26.7 F)
2018-34.5 C (-30.1 F)
2019-30.2 C (-22.4 F)
2020-27.5 C (-17.5 F)
2021-30.8 C (-23.4 F)
2022-27.6 C (-17.7 F)
2023-30.4 C (-22.7 F)
2024-38.1 C (-36.6 F)
2025-25.6 C (-14.1 F)
2026-35.1 C (-31.2 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Bortnan_A by year The wettest day of the year at Bortnan_A, 1995 to 2026. The record is 66.0 mm (2.6 in) in 2023, marked on the chart; the median year is 27.1 mm (1.1 in). 020406080200020102020Record: 66.0 mm (2.6 in) in 2023
The wettest day of the year at Bortnan_A, 1995 to 2026. The record is 66.0 mm (2.6 in) in 2023, marked on the chart; the median year is 27.1 mm (1.1 in).
Wettest day (Rx1day) at Bortnan_A by year
YearWettest day (Rx1day)
19950.6 mm (0.02 in)
199616.7 mm (0.7 in)
199718.4 mm (0.7 in)
199843.7 mm (1.7 in)
199917.9 mm (0.7 in)
200035.7 mm (1.4 in)
200126.2 mm (1.0 in)
200227.5 mm (1.1 in)
200337.6 mm (1.5 in)
200419.3 mm (0.8 in)
200527.4 mm (1.1 in)
200626.7 mm (1.1 in)
200714.0 mm (0.6 in)
200821.6 mm (0.9 in)
200940.0 mm (1.6 in)
201025.2 mm (1.0 in)
201133.4 mm (1.3 in)
201221.2 mm (0.8 in)
201330.3 mm (1.2 in)
201434.3 mm (1.4 in)
201525.6 mm (1.0 in)
201629.5 mm (1.2 in)
201743.4 mm (1.7 in)
201822.8 mm (0.9 in)
201919.1 mm (0.8 in)
202023.5 mm (0.9 in)
202130.3 mm (1.2 in)
202233.9 mm (1.3 in)
202366.0 mm (2.6 in)
202424.2 mm (1.0 in)
202533.5 mm (1.3 in)
202630.2 mm (1.2 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Bortnan_A by year The wettest five days of the year at Bortnan_A, 1995 to 2026. The record is 86.3 mm (3.4 in) in 2023, marked on the chart; the median year is 52.0 mm (2.0 in). 0255075100200020102020Record: 86.3 mm (3.4 in) in 2023
The wettest five days of the year at Bortnan_A, 1995 to 2026. The record is 86.3 mm (3.4 in) in 2023, marked on the chart; the median year is 52.0 mm (2.0 in).
Wettest five days (Rx5day) at Bortnan_A by year
YearWettest five days (Rx5day)
19951.0 mm (0.04 in)
199634.3 mm (1.4 in)
199733.1 mm (1.3 in)
199860.8 mm (2.4 in)
199931.5 mm (1.2 in)
200061.2 mm (2.4 in)
200159.5 mm (2.3 in)
200249.7 mm (2.0 in)
200353.1 mm (2.1 in)
200448.2 mm (1.9 in)
200551.9 mm (2.0 in)
200655.0 mm (2.2 in)
200740.8 mm (1.6 in)
200852.1 mm (2.1 in)
200962.4 mm (2.5 in)
201053.9 mm (2.1 in)
201156.9 mm (2.2 in)
201261.6 mm (2.4 in)
201351.7 mm (2.0 in)
201454.6 mm (2.1 in)
201544.8 mm (1.8 in)
201641.2 mm (1.6 in)
201752.5 mm (2.1 in)
201839.7 mm (1.6 in)
201933.7 mm (1.3 in)
202036.7 mm (1.4 in)
202156.7 mm (2.2 in)
202268.2 mm (2.7 in)
202386.3 mm (3.4 in)
202446.2 mm (1.8 in)
202569.6 mm (2.7 in)
202645.7 mm (1.8 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Bortnan_A by year The longest dry spell of the year at Bortnan_A, 1995 to 2026. The record is 55 days in 2003, marked on the chart; the median year is 25 days. 0204060200020102020Record: 55 days in 2003
The longest dry spell of the year at Bortnan_A, 1995 to 2026. The record is 55 days in 2003, marked on the chart; the median year is 25 days.
Longest dry spell (CDD) at Bortnan_A by year
YearLongest dry spell (CDD)
199518 days
199635 days
199726 days
199822 days
199913 days
200026 days
200115 days
200236 days
200355 days
200431 days
200518 days
200622 days
200722 days
200822 days
200921 days
201032 days
201120 days
201226 days
201333 days
201427 days
201523 days
201622 days
201735 days
201832 days
201923 days
202020 days
202130 days
202237 days
202335 days
202418 days
202518 days
202635 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

30 years with a frost

Across 30 years with a frost, the median last spring frost at Bortnan_A falls on 21 June and the median first autumn frost on 15 July, which leaves a median of 26 days between them.

Fitted over all years, the growing season changes by -0.7 days per decade at this station.

Frost dates and growing season at Bortnan_A
MeasureMedian, all yearsEarliest periodRecent period (1996 to 2025)Recent against earliestFitted trend
Last spring frost21 Junen/a21 Junen/a+0.1 days per decade
First autumn frost15 Julyn/a15 Julyn/a-0.6 days per decade
Growing days26 daysn/a26 daysn/a-0.7 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

30 years, 1996 to 2025

A day with at least 26.9 mm (1.1 in) of rain is expected about once in 2 years. A day with at least 64.3 mm (2.5 in) of rain is expected about once in 100 years.

Rainfall return levels at Bortnan_A: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years26.9 mm (1.1 in)
5 years36.0 mm (1.4 in)
10 years42.4 mm (1.7 in)
25 years50.8 mm (2.0 in)
50 years57.5 mm (2.3 in)Longer than the 30 years of record
100 years64.3 mm (2.5 in)Longer than the 30 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, 30 years of values from 1996 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: 66.0 mm (2.6 in) in 2023; 43.7 mm (1.7 in) in 1998; 43.4 mm (1.7 in) in 2017.

Download the Data

  • Data for Bortnan_A standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Bortnan_A 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 (2026-10-12).