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Karuizawa Weather Records (JA000047622)

Record envelope, standing records and threshold days for Karuizawa (JA000047622), Japan, with 76 years of record.

Key Facts for Karuizawa

  • Karuizawa (JA000047622) is a weather station in Japan at 36.35 latitude and 138.55 longitude, 1,004 m (3,294 ft) above sea level.
  • The station reports from 1951 to 2026, 76 years of record.
  • 1,464 records set at Karuizawa still stand.
  • Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
  • Karuizawa set a daily record precipitation of 80.5 mm (3.2 in) on 29 September 2026 (provisional).

Provisional Records

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

About the Station

  • Location: Japan, 36.35 latitude, 138.55 longitude.
  • Elevation: 1,004 m (3,294 ft).
  • Period of record: 1951 to 2026, 76 years.
  • Eligible elements: tmax, tmin, prcp.

Daily Record Envelope and 2026

4 days at or beyond a record
Daily record high and record low at Karuizawa, with 2026 drawn through them The band shows the record high and record low for each calendar day at Karuizawa. The lines show the 2026 daily maximum and minimum. 4 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -2002040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Karuizawa. The lines show the 2026 daily maximum and minimum. 4 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Karuizawa, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan16.1 C (61.0 F)-18.8 C (-1.8 F)10.9 C (51.6 F)-13.9 C (7.0 F)
Feb18.8 C (65.8 F)-19.1 C (-2.4 F)16.0 C (60.8 F)-14.1 C (6.6 F)
Mar21.8 C (71.2 F)-17.4 C (0.7 F)12.7 C (54.9 F)-8.2 C (17.2 F)
Apr28.3 C (82.9 F)-11.6 C (11.1 F)21.1 C (70.0 F)-4.5 C (23.9 F)
May29.5 C (85.1 F)-4.9 C (23.2 F)26.4 C (79.5 F)-1.2 C (29.8 F)
Jun32.1 C (89.8 F)-0.3 C (31.5 F)25.1 C (77.2 F)8.4 C (47.1 F)
Jul33.1 C (91.6 F)5.0 C (41.0 F)31.8 C (89.2 F)13.7 C (56.7 F)
Aug33.5 C (92.3 F)7.0 C (44.6 F)30.1 C (86.2 F)15.2 C (59.4 F)
Sep31.1 C (88.0 F)1.1 C (34.0 F)26.2 C (79.2 F)12.2 C (54.0 F)
Oct26.2 C (79.2 F)-6.0 C (21.2 F)21.1 C (70.0 F)3.9 C (39.0 F)
Nov23.3 C (73.9 F)-11.1 C (12.0 F)n/an/a
Dec20.4 C (68.7 F)-18.0 C (-0.4 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Karuizawa by the year they were set 1,464 records at Karuizawa still stand. 2025 holds the most, with 59. 02040601965: 411966: 311967: 231968: 271969: 431970: 351971: 361972: 261973: 381974: 201975: 221976: 451977: 341978: 281979: 291980: 361981: 431982: 421983: 191984: 401985: 251986: 331987: 391988: 341989: 261990: 11991: 11994: 161995: 141996: 191997: 221998: 161999: 102000: 102001: 122002: 212003: 192004: 152006: 122007: 152008: 112009: 122010: 392011: 222012: 122013: 352014: 182015: 262016: 132017: 112018: 332019: 112020: 242021: 162022: 242023: 262024: 242025: 592026: 301965197119771983198919972003201020162022
1,464 records at Karuizawa still stand. 2025 holds the most, with 59.
Standing records at Karuizawa by the year they were set
Year setStanding records
196541
196631
196723
196827
196943
197035
197136
197226
197338
197420
197522
197645
197734
197828
197929
198036
198143
198242
198319
198440
198525
198633
198739
198834
198926
19901
19911
199416
199514
199619
199722
199816
199910
200010
200112
200221
200319
200415
200612
200715
200811
200912
201039
201122
201212
201335
201418
201526
201613
201711
201833
201911
202024
202116
202224
202326
202424
202559
202630

All-Time Record Progression

6 new records
When Karuizawa set new all-time records 6 all-time records were set at Karuizawa between 23 July 2000 and 5 August 2025. Each dot is a new record. Record high maximum temperatureRecord daily precipitationRecord high minimum temperature23 July 2000: Record high maximum temperature 33.1 C (91.6 F)11 August 2013: Record high maximum temperature 33.5 C (92.3 F)12 October 2019: Record daily precipitation 319.0 mm (12.6 in)7 July 2025: Record high minimum temperature 21.5 C (70.7 F)4 August 2025: Record high minimum temperature 21.6 C (70.9 F)5 August 2025: Record high minimum temperature 22.2 C (72.0 F)200020052010201520202025
6 all-time records were set at Karuizawa between 23 July 2000 and 5 August 2025. Each dot is a new record.
When Karuizawa set new all-time records
DateKindDetail
2000-07-23Record high maximum temperatureRecord high maximum temperature 33.1 C (91.6 F)
2013-08-11Record high maximum temperatureRecord high maximum temperature 33.5 C (92.3 F)
2019-10-12Record daily precipitationRecord daily precipitation 319.0 mm (12.6 in)
2025-07-07Record high minimum temperatureRecord high minimum temperature 21.5 C (70.7 F)
2025-08-04Record high minimum temperatureRecord high minimum temperature 21.6 C (70.9 F)
2025-08-05Record high minimum temperatureRecord high minimum temperature 22.2 C (72.0 F)

Wettest Day of Each Month

Oct: 319.0 mm (12.6 in)
Record daily precipitation for each month at Karuizawa The wettest day on record for each calendar month at Karuizawa. The most was 319.0 mm (12.6 in) on 12 October 2019. 0100200300400 Jan: 43.0 mm (1.7 in), 31 January 1970 Jan Feb: 70.1 mm (2.8 in), 15 February 2014 Feb Mar: 51.1 mm (2.0 in), 29 March 2020 Mar Apr: 71.4 mm (2.8 in), 8 April 2008 Apr May: 76.0 mm (3.0 in), 3 May 1965 May Jun: 96.8 mm (3.8 in), 28 June 1966 Jun Jul: 185.0 mm (7.3 in), 2 July 2026 Jul Aug: 271.7 mm (10.7 in), 13 August 1959 Aug Sep: 240.5 mm (9.5 in), 7 September 2007 Sep Oct: 319.0 mm (12.6 in), 12 October 2019 Oct Nov: 71.1 mm (2.8 in), 2 November 2024 Nov Dec: 60.5 mm (2.4 in), 27 December 2006 Dec
The wettest day on record for each calendar month at Karuizawa. The most was 319.0 mm (12.6 in) on 12 October 2019.
Record daily precipitation for each month at Karuizawa
MonthRecord daily precipitation (mm)Date
Jan43.0 mm (1.7 in)31 January 1970
Feb70.1 mm (2.8 in)15 February 2014
Mar51.1 mm (2.0 in)29 March 2020
Apr71.4 mm (2.8 in)8 April 2008
May76.0 mm (3.0 in)3 May 1965
Jun96.8 mm (3.8 in)28 June 1966
Jul185.0 mm (7.3 in)2 July 2026
Aug271.7 mm (10.7 in)13 August 1959
Sep240.5 mm (9.5 in)7 September 2007
Oct319.0 mm (12.6 in)12 October 2019
Nov71.1 mm (2.8 in)2 November 2024
Dec60.5 mm (2.4 in)27 December 2006

Period of Record Coverage

1965 to 2026
Days with data per year at Karuizawa 61 years of record at Karuizawa, 1965 to 2026. 11 years have data for under 90 percent of days and are left out of rankings: 1990, 1991, 1992, 1993, 1994, 1997, 2001, 2020 and others. 1965: 365 of 365 days1966: 365 of 365 days1967: 365 of 365 days1968: 366 of 366 days1969: 365 of 365 days1970: 365 of 365 days1971: 365 of 365 days1972: 366 of 366 days1973: 365 of 365 days1974: 365 of 365 days1975: 365 of 365 days1976: 366 of 366 days1977: 365 of 365 days1978: 365 of 365 days1979: 365 of 365 days1980: 366 of 366 days1981: 365 of 365 days1982: 365 of 365 days1983: 365 of 365 days1984: 366 of 366 days1985: 365 of 365 days1986: 365 of 365 days1987: 365 of 365 days1988: 366 of 366 days1989: 365 of 365 days1990: 5 of 365 days1991: 4 of 365 days1992: 1 of 366 days1993: 4 of 365 days1994: 268 of 365 days1995: 330 of 365 days1996: 351 of 366 days1997: 327 of 365 days1998: 342 of 365 days1999: 329 of 365 days2000: 344 of 366 days2001: 297 of 365 days2002: 339 of 365 days2003: 339 of 365 days2004: 338 of 366 days2006: 349 of 365 days2007: 352 of 365 days2008: 356 of 366 days2009: 348 of 365 days2010: 343 of 365 days2011: 354 of 365 days2012: 353 of 366 days2013: 356 of 365 days2014: 349 of 365 days2015: 345 of 365 days2016: 349 of 366 days2017: 344 of 365 days2018: 347 of 365 days2019: 341 of 365 days2020: 324 of 366 days2021: 335 of 365 days2022: 347 of 365 days2023: 263 of 365 days2024: 297 of 366 days2025: 356 of 365 days2026: 274 of 365 days197019801990200020102020
61 years of record at Karuizawa, 1965 to 2026. 11 years have data for under 90 percent of days and are left out of rankings: 1990, 1991, 1992, 1993, 1994, 1997, 2001, 2020 and others.
Days with data per year at Karuizawa
YearDays with dataShare of yearComplete
1965365100%Yes
1966365100%Yes
1967365100%Yes
1968366100%Yes
1969365100%Yes
1970365100%Yes
1971365100%Yes
1972366100%Yes
1973365100%Yes
1974365100%Yes
1975365100%Yes
1976366100%Yes
1977365100%Yes
1978365100%Yes
1979365100%Yes
1980366100%Yes
1981365100%Yes
1982365100%Yes
1983365100%Yes
1984366100%Yes
1985365100%Yes
1986365100%Yes
1987365100%Yes
1988366100%Yes
1989365100%Yes
199051%No
199141%No
199210%No
199341%No
199426873%No
199533090%Yes
199635196%Yes
199732790%No
199834294%Yes
199932990%Yes
200034494%Yes
200129781%No
200233993%Yes
200333993%Yes
200433892%Yes
200634996%Yes
200735296%Yes
200835697%Yes
200934895%Yes
201034394%Yes
201135497%Yes
201235396%Yes
201335698%Yes
201434996%Yes
201534595%Yes
201634995%Yes
201734494%Yes
201834795%Yes
201934193%Yes
202032489%No
202133592%Yes
202234795%Yes
202326372%No
202429781%No
202535698%Yes
202627475%No

Latest Records

20
Latest records at Karuizawa
DateStationRecordValueBeat old record byOld record stoodSignificance
29 September 2026Karuizawa, JPdaily rain (Provisional)80.5 mm (3.2 in)35.5 mm (1.4 in)40 years36 of 100 (Notable)
28 September 2026Karuizawa, JPall-time rain (Provisional)343.5 mm (13.5 in)24.5 mm (1.0 in)6 years40 of 100 (Notable)
20 September 2026Karuizawa, JPmonthly rain (Provisional)265.5 mm (10.5 in)25.0 mm (1.0 in)19 years34 of 100 (Routine)
19 September 2026Karuizawa, JPdaily high min (Provisional)17.4 C (63.3 F)0.2 C (0.4 F)3 years6 of 100 (Routine)
16 September 2026Karuizawa, JPdaily rain (Provisional)183.0 mm (7.2 in)57.0 mm (2.2 in)28 years42 of 100 (Notable)
15 September 2026Karuizawa, JPdaily rain (Provisional)125.0 mm (4.9 in)75.8 mm (3.0 in)73 years65 of 100 (Major)
14 September 2026Karuizawa, JPdaily rain (Provisional)55.5 mm (2.2 in)0.4 mm (0.02 in)35 years17 of 100 (Routine)
11 September 2026Karuizawa, JPdaily rain (Provisional)181.0 mm (7.1 in)126.1 mm (5.0 in)25 years54 of 100 (Notable)
10 September 2026Karuizawa, JPdaily rain (Provisional)172.0 mm (6.8 in)139.0 mm (5.5 in)44 years60 of 100 (Major)
8 September 2026Karuizawa, JPdaily rain (Provisional)71.5 mm (2.8 in)22.5 mm (0.9 in)45 years30 of 100 (Routine)
4 September 2026Karuizawa, JPdaily rain (Provisional)53.0 mm (2.1 in)0.9 mm (0.04 in)4 years8 of 100 (Routine)
2 September 2026Karuizawa, JPdaily high min (Provisional)19.9 C (67.8 F)0.4 C (0.7 F)15 years11 of 100 (Routine)
29 August 2026Karuizawa, JPdaily low max (Provisional)16.9 C (62.4 F)0.9 C (1.6 F)11 years11 of 100 (Routine)
27 August 2026Karuizawa, JPdaily rain (Provisional)177.0 mm (7.0 in)86.1 mm (3.4 in)9 years49 of 100 (Notable)
15 August 2026Karuizawa, JPdaily rain91.5 mm (3.6 in)19.5 mm (0.8 in)43 years29 of 100 (Routine)
7 August 2026Karuizawa, JPdaily high min19.9 C (67.8 F)0.3 C (0.5 F)8 years9 of 100 (Routine)
6 August 2026Karuizawa, JPdaily high min21.1 C (70.0 F)0.8 C (1.4 F)3 years9 of 100 (Routine)
25 July 2026Karuizawa, JPdaily high min19.4 C (66.9 F)0.8 C (1.4 F)12 years12 of 100 (Routine)
24 July 2026Karuizawa, JPdaily high min20.4 C (68.7 F)0.2 C (0.4 F)17 years11 of 100 (Routine)
23 July 2026Karuizawa, JPdaily high min20.9 C (69.6 F)0.8 C (1.4 F)17 years14 of 100 (Routine)

Climate Trend

26 complete years, 1965 to 2025
Annual mean temperature at Karuizawa as warming stripes, 1965 to 2025 One stripe for each of 26 complete years at Karuizawa, 1965 to 2025. Blue stripes are years cooler than the station's own mean of 8.1 C (46.6 F); red stripes are warmer. The coolest year was 1984, at 7.1 C (44.7 F), and the warmest was 2025, at 10.4 C (50.6 F). The strongest colour marks a difference of 2.3 C (4.1 F). 1965: 7.9 C, -0.3 C from the station mean1966: 8.5 C, +0.4 C from the station mean1967: 8.5 C, +0.3 C from the station mean1968: 8.3 C, +0.1 C from the station mean1969: 8.2 C, 0.0 C from the station mean1970: 7.8 C, -0.3 C from the station mean1971: 8.1 C, -0.1 C from the station mean1972: 8.5 C, +0.4 C from the station mean1973: 8.4 C, +0.3 C from the station mean1974: 7.7 C, -0.4 C from the station mean1975: 8.0 C, -0.1 C from the station mean1976: 7.6 C, -0.5 C from the station mean1977: 8.2 C, +0.1 C from the station mean1978: 8.2 C, 0.0 C from the station mean1979: 9.2 C, +1.0 C from the station mean1980: 7.6 C, -0.5 C from the station mean1981: 7.1 C, -1.0 C from the station mean1982: 7.9 C, -0.2 C from the station mean1983: 7.8 C, -0.4 C from the station mean1984: 7.1 C, -1.1 C from the station mean1985: 8.2 C, 0.0 C from the station mean1986: 7.5 C, -0.7 C from the station mean1987: 8.6 C, +0.4 C from the station mean1988: 7.8 C, -0.4 C from the station mean1989: 8.7 C, +0.5 C from the station mean2025: 10.4 C, +2.2 C from the station mean1965197019801990200020102020
One stripe for each of 26 complete years at Karuizawa, 1965 to 2025. Blue stripes are years cooler than the station's own mean of 8.1 C (46.6 F); red stripes are warmer. The coolest year was 1984, at 7.1 C (44.7 F), and the warmest was 2025, at 10.4 C (50.6 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Karuizawa as warming stripes, 1965 to 2025
YearAnnual mean temperatureDifference from the station mean
19657.9 C-0.25 C
19668.5 C+0.41 C
19678.5 C+0.32 C
19688.3 C+0.15 C
19698.2 C+0.03 C
19707.8 C-0.33 C
19718.1 C-0.06 C
19728.5 C+0.40 C
19738.4 C+0.26 C
19747.7 C-0.42 C
19758.0 C-0.09 C
19767.6 C-0.49 C
19778.2 C+0.10 C
19788.2 C+0.04 C
19799.2 C+1.05 C
19807.6 C-0.51 C
19817.1 C-1.02 C
19827.9 C-0.21 C
19837.8 C-0.36 C
19847.1 C-1.08 C
19858.2 C+0.04 C
19867.5 C-0.68 C
19878.6 C+0.45 C
19887.8 C-0.38 C
19898.7 C+0.53 C
202510.4 C+2.22 C

This station does not have enough complete years (30 are needed) to fit a temperature trend.

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

1951 to 2026
Yearly extremes at Karuizawa: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)33.5 C (92.3 F)201331.0 C (87.8 F)61
Coldest night (TNn)-19.1 C (-2.4 F)1984-15.6 C (3.9 F)61
Wettest day (Rx1day)343.5 mm (13.5 in)202677.0 mm (3.0 in)74
Wettest five days (Rx5day)501.0 mm (19.7 in)2026129.3 mm (5.1 in)66
Longest dry spell (CDD)44 days198619 days69

Hottest day (TXx)

Hottest day (TXx) at Karuizawa by year The hottest day of the year at Karuizawa, 1951 to 2026. The record is 33.5 C (92.3 F) in 2013, marked on the chart; the median year is 31.0 C (87.8 F). 22.52527.53032.5351960198020002020Record: 33.5 C (92.3 F) in 2013
The hottest day of the year at Karuizawa, 1951 to 2026. The record is 33.5 C (92.3 F) in 2013, marked on the chart; the median year is 31.0 C (87.8 F).
Hottest day (TXx) at Karuizawa by year
YearHottest day (TXx)
1951n/a
1952n/a
1953n/a
1954n/a
1955n/a
1956n/a
1957n/a
1958n/a
1959n/a
1960n/a
1961n/a
1962n/a
1963n/a
1964n/a
196530.6 C (87.1 F)
196630.9 C (87.6 F)
196731.5 C (88.7 F)
196832.0 C (89.6 F)
196929.5 C (85.1 F)
197031.4 C (88.5 F)
197131.1 C (88.0 F)
197229.9 C (85.8 F)
197331.3 C (88.3 F)
197429.0 C (84.2 F)
197530.3 C (86.5 F)
197629.0 C (84.2 F)
197730.7 C (87.3 F)
197831.3 C (88.3 F)
197930.6 C (87.1 F)
198030.5 C (86.9 F)
198129.6 C (85.3 F)
198229.0 C (84.2 F)
198330.6 C (87.1 F)
198430.3 C (86.5 F)
198530.2 C (86.4 F)
198629.7 C (85.5 F)
198731.1 C (88.0 F)
198830.1 C (86.2 F)
198929.2 C (84.6 F)
199024.7 C (76.5 F)
199127.0 C (80.6 F)
199227.2 C (81.0 F)
199324.7 C (76.5 F)
199432.4 C (90.3 F)
199532.0 C (89.6 F)
199631.6 C (88.9 F)
199730.3 C (86.5 F)
199831.0 C (87.8 F)
199929.9 C (85.8 F)
200033.1 C (91.6 F)
200131.3 C (88.3 F)
200232.2 C (90.0 F)
200330.6 C (87.1 F)
200432.1 C (89.8 F)
200630.9 C (87.6 F)
200732.3 C (90.1 F)
200831.1 C (88.0 F)
200930.1 C (86.2 F)
201031.5 C (88.7 F)
201131.2 C (88.2 F)
201231.5 C (88.7 F)
201333.5 C (92.3 F)
201431.5 C (88.7 F)
201531.9 C (89.4 F)
201630.8 C (87.4 F)
201730.3 C (86.5 F)
201832.9 C (91.2 F)
201931.5 C (88.7 F)
202031.9 C (89.4 F)
202130.3 C (86.5 F)
202232.1 C (89.8 F)
202331.8 C (89.2 F)
202432.1 C (89.8 F)
202531.4 C (88.5 F)
202631.8 C (89.2 F)

Coldest night (TNn)

Coldest night (TNn) at Karuizawa by year The coldest night of the year at Karuizawa, 1951 to 2026. The record is -19.1 C (-2.4 F) in 1984, marked on the chart; the median year is -15.6 C (3.9 F). -20-10010201960198020002020Record: -19.1 C (-2.4 F) in 1984
The coldest night of the year at Karuizawa, 1951 to 2026. The record is -19.1 C (-2.4 F) in 1984, marked on the chart; the median year is -15.6 C (3.9 F).
Coldest night (TNn) at Karuizawa by year
YearColdest night (TNn)
1951n/a
1952n/a
1953n/a
1954n/a
1955n/a
1956n/a
1957n/a
1958n/a
1959n/a
1960n/a
1961n/a
1962n/a
1963n/a
1964n/a
1965-13.8 C (7.2 F)
1966-16.1 C (3.0 F)
1967-17.1 C (1.2 F)
1968-16.8 C (1.8 F)
1969-14.8 C (5.4 F)
1970-17.4 C (0.7 F)
1971-15.6 C (3.9 F)
1972-15.3 C (4.5 F)
1973-16.9 C (1.6 F)
1974-18.0 C (-0.4 F)
1975-15.9 C (3.4 F)
1976-16.4 C (2.5 F)
1977-18.8 C (-1.8 F)
1978-18.0 C (-0.4 F)
1979-13.5 C (7.7 F)
1980-17.1 C (1.2 F)
1981-18.5 C (-1.3 F)
1982-18.1 C (-0.6 F)
1983-18.4 C (-1.1 F)
1984-19.1 C (-2.4 F)
1985-18.4 C (-1.1 F)
1986-16.8 C (1.8 F)
1987-14.5 C (5.9 F)
1988-15.5 C (4.1 F)
1989-14.0 C (6.8 F)
19906.3 C (43.3 F)
199115.1 C (59.2 F)
199218.4 C (65.1 F)
199314.2 C (57.6 F)
1994-12.2 C (10.0 F)
1995-16.6 C (2.1 F)
1996-18.2 C (-0.8 F)
1997-14.6 C (5.7 F)
1998-17.1 C (1.2 F)
1999-16.7 C (1.9 F)
2000-16.0 C (3.2 F)
2001-17.9 C (-0.2 F)
2002-16.9 C (1.6 F)
2003-16.7 C (1.9 F)
2004-13.5 C (7.7 F)
2006-15.1 C (4.8 F)
2007-12.4 C (9.7 F)
2008-15.9 C (3.4 F)
2009-14.4 C (6.1 F)
2010-14.8 C (5.4 F)
2011-15.2 C (4.6 F)
2012-18.6 C (-1.5 F)
2013-15.8 C (3.6 F)
2014-14.2 C (6.4 F)
2015-13.7 C (7.3 F)
2016-16.0 C (3.2 F)
2017-15.0 C (5.0 F)
2018-14.9 C (5.2 F)
2019-11.3 C (11.7 F)
2020-13.0 C (8.6 F)
2021-12.0 C (10.4 F)
2022-14.2 C (6.4 F)
2023-16.2 C (2.8 F)
2024-10.8 C (12.6 F)
2025-11.6 C (11.1 F)
2026-14.1 C (6.6 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Karuizawa by year The wettest day of the year at Karuizawa, 1951 to 2026. The record is 343.5 mm (13.5 in) in 2026, marked on the chart; the median year is 77.0 mm (3.0 in). 01002003004001960198020002020Record: 343.5 mm (13.5 in) in 2026
The wettest day of the year at Karuizawa, 1951 to 2026. The record is 343.5 mm (13.5 in) in 2026, marked on the chart; the median year is 77.0 mm (3.0 in).
Wettest day (Rx1day) at Karuizawa by year
YearWettest day (Rx1day)
195150.2 mm (2.0 in)
195249.2 mm (1.9 in)
195360.7 mm (2.4 in)
195457.9 mm (2.3 in)
195592.0 mm (3.6 in)
195653.9 mm (2.1 in)
195748.1 mm (1.9 in)
1958141.0 mm (5.6 in)
1959271.7 mm (10.7 in)
196080.3 mm (3.2 in)
1961149.2 mm (5.9 in)
196245.5 mm (1.8 in)
196352.5 mm (2.1 in)
196456.1 mm (2.2 in)
196591.4 mm (3.6 in)
196696.8 mm (3.8 in)
196766.6 mm (2.6 in)
196899.0 mm (3.9 in)
196956.5 mm (2.2 in)
197087.5 mm (3.4 in)
1971129.0 mm (5.1 in)
197273.5 mm (2.9 in)
197361.5 mm (2.4 in)
1974113.5 mm (4.5 in)
197548.0 mm (1.9 in)
197653.5 mm (2.1 in)
197778.0 mm (3.1 in)
197853.0 mm (2.1 in)
197975.5 mm (3.0 in)
198050.0 mm (2.0 in)
1981135.0 mm (5.3 in)
1982160.5 mm (6.3 in)
1983112.0 mm (4.4 in)
198471.5 mm (2.8 in)
198584.0 mm (3.3 in)
1986108.5 mm (4.3 in)
198768.5 mm (2.7 in)
198848.5 mm (1.9 in)
1989125.0 mm (4.9 in)
199067.1 mm (2.6 in)
199175.9 mm (3.0 in)
1992n/a
199384.1 mm (3.3 in)
199458.9 mm (2.3 in)
199587.9 mm (3.5 in)
199675.9 mm (3.0 in)
199730.0 mm (1.2 in)
1998126.0 mm (5.0 in)
1999149.1 mm (5.9 in)
2000101.1 mm (4.0 in)
200171.1 mm (2.8 in)
200288.9 mm (3.5 in)
200363.0 mm (2.5 in)
2004126.5 mm (5.0 in)
2006144.0 mm (5.7 in)
2007240.5 mm (9.5 in)
200882.5 mm (3.2 in)
200989.2 mm (3.5 in)
201069.1 mm (2.7 in)
201173.2 mm (2.9 in)
201255.9 mm (2.2 in)
2013110.0 mm (4.3 in)
201470.1 mm (2.8 in)
201587.1 mm (3.4 in)
201690.9 mm (3.6 in)
201778.0 mm (3.1 in)
201854.1 mm (2.1 in)
2019319.0 mm (12.6 in)
202051.1 mm (2.0 in)
2021119.9 mm (4.7 in)
202241.9 mm (1.6 in)
202331.0 mm (1.2 in)
202479.5 mm (3.1 in)
202538.0 mm (1.5 in)
2026343.5 mm (13.5 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Karuizawa by year The wettest five days of the year at Karuizawa, 1951 to 2026. The record is 501.0 mm (19.7 in) in 2026, marked on the chart; the median year is 129.3 mm (5.1 in). 02004006001960198020002020Record: 501.0 mm (19.7 in) in 2026
The wettest five days of the year at Karuizawa, 1951 to 2026. The record is 501.0 mm (19.7 in) in 2026, marked on the chart; the median year is 129.3 mm (5.1 in).
Wettest five days (Rx5day) at Karuizawa by year
YearWettest five days (Rx5day)
1951133.2 mm (5.2 in)
195282.7 mm (3.3 in)
1953138.4 mm (5.4 in)
1954103.1 mm (4.1 in)
1955116.3 mm (4.6 in)
1956160.2 mm (6.3 in)
195798.7 mm (3.9 in)
1958173.3 mm (6.8 in)
1959340.2 mm (13.4 in)
1960112.8 mm (4.4 in)
1961232.4 mm (9.1 in)
1962111.9 mm (4.4 in)
196398.5 mm (3.9 in)
1964128.1 mm (5.0 in)
1965142.3 mm (5.6 in)
1966159.9 mm (6.3 in)
1967113.7 mm (4.5 in)
1968142.5 mm (5.6 in)
196978.5 mm (3.1 in)
1970160.0 mm (6.3 in)
1971173.0 mm (6.8 in)
1972168.0 mm (6.6 in)
197398.0 mm (3.9 in)
1974140.5 mm (5.5 in)
1975125.5 mm (4.9 in)
1976103.0 mm (4.1 in)
197781.5 mm (3.2 in)
197883.0 mm (3.3 in)
1979142.5 mm (5.6 in)
1980115.5 mm (4.5 in)
1981206.5 mm (8.1 in)
1982265.5 mm (10.5 in)
1983210.5 mm (8.3 in)
1984133.5 mm (5.3 in)
1985167.5 mm (6.6 in)
1986154.0 mm (6.1 in)
1987112.0 mm (4.4 in)
1988100.5 mm (4.0 in)
1989163.5 mm (6.4 in)
1990n/a
1991n/a
1992n/a
1993n/a
1994n/a
1995n/a
1996n/a
199753.6 mm (2.1 in)
199899.8 mm (3.9 in)
1999192.6 mm (7.6 in)
2000n/a
2001n/a
200276.2 mm (3.0 in)
200398.6 mm (3.9 in)
2004152.4 mm (6.0 in)
2006285.5 mm (11.2 in)
2007398.0 mm (15.7 in)
2008119.6 mm (4.7 in)
2009104.2 mm (4.1 in)
2010144.4 mm (5.7 in)
2011103.9 mm (4.1 in)
201281.3 mm (3.2 in)
2013129.0 mm (5.1 in)
2014110.0 mm (4.3 in)
2015137.9 mm (5.4 in)
2016176.8 mm (7.0 in)
2017176.8 mm (7.0 in)
2018100.1 mm (3.9 in)
2019343.3 mm (13.5 in)
2020129.5 mm (5.1 in)
2021243.8 mm (9.6 in)
2022100.1 mm (3.9 in)
202351.1 mm (2.0 in)
2024119.6 mm (4.7 in)
202556.0 mm (2.2 in)
2026501.0 mm (19.7 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Karuizawa by year The longest dry spell of the year at Karuizawa, 1951 to 2026. The record is 44 days in 1986, marked on the chart; the median year is 19 days. 02040601960198020002020Record: 44 days in 1986
The longest dry spell of the year at Karuizawa, 1951 to 2026. The record is 44 days in 1986, marked on the chart; the median year is 19 days.
Longest dry spell (CDD) at Karuizawa by year
YearLongest dry spell (CDD)
195123 days
195215 days
195331 days
195421 days
195523 days
195622 days
195724 days
195814 days
195924 days
196023 days
196124 days
196223 days
196323 days
196417 days
196524 days
196623 days
196715 days
196829 days
196918 days
197025 days
197128 days
197212 days
197325 days
197419 days
197522 days
197625 days
197725 days
197815 days
197921 days
198026 days
198121 days
198219 days
198316 days
198421 days
198527 days
198644 days
198718 days
198823 days
198927 days
1990n/a
1991n/a
1992n/a
1993n/a
19941 day
19951 day
19961 day
19972 days
19982 days
19999 days
2000n/a
2001n/a
20023 days
20036 days
200414 days
200618 days
200729 days
200812 days
200914 days
201020 days
201115 days
201218 days
201315 days
201415 days
201521 days
201617 days
201725 days
201817 days
201921 days
202014 days
202113 days
202223 days
202314 days
202419 days
202513 days
202611 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

26 years with a frost

Across 26 years with a frost, the median last spring frost at Karuizawa falls on 14 May and the median first autumn frost on 17 October, which leaves a median of 156 days between them.

Fitted over all years, the growing season changes by +3.0 days per decade at this station.

Frost dates and growing season at Karuizawa
MeasureMedian, all yearsEarliest periodRecent period (1965 to 2025)Recent against earliestFitted trend
Last spring frost14 Mayn/a14 Mayn/a-0.9 days per decade
First autumn frost17 Octobern/a17 Octobern/a+2.1 days per decade
Growing days156 daysn/a156 daysn/a+3.0 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

56 years, 1951 to 2022

A day with at least 77.1 mm (3.0 in) of rain is expected about once in 2 years. A day with at least 326.4 mm (12.9 in) of rain is expected about once in 100 years.

Rainfall return levels at Karuizawa: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years77.1 mm (3.0 in)
5 years115.6 mm (4.6 in)
10 years149.7 mm (5.9 in)
25 years205.9 mm (8.1 in)
50 years259.8 mm (10.2 in)
100 years326.4 mm (12.9 in)Longer than the 56 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, 56 years of values from 1951 to 2022.

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: 319.0 mm (12.6 in) in 2019; 271.7 mm (10.7 in) in 1959; 240.5 mm (9.5 in) in 2007.

Download the Data

  • Data for Karuizawa standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Karuizawa 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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-15).