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Data as of 2025-12-31
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Built 2026-10-18 (18 October 2026)

Iruma Weather Records (JAW00043309)

Record envelope, standing records and threshold days for Iruma (JAW00043309), Japan, with 78 years of record.

Key Facts for Iruma

  • Iruma (JAW00043309) is a weather station in Japan at 35.83 latitude and 139.42 longitude, 94 m (309 ft) above sea level.
  • The station reports from 1949 to 2026, 78 years of record.
  • 1,464 records set at Iruma still stand.
  • Records are tracked for no element yet: an element needs 30 years of data to be eligible.

About the Station

  • Location: Japan, 35.83 latitude, 139.42 longitude.
  • Elevation: 94 m (309 ft).
  • Period of record: 1949 to 2026, 78 years.
  • Eligible elements: none yet.

Daily Record Envelope and 2026

76 days at or beyond a record
Daily record high and record low at Iruma, with 2026 drawn through them The band shows the record high and record low for each calendar day at Iruma. The lines show the 2026 daily maximum and minimum. 76 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -10010203040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Iruma. The lines show the 2026 daily maximum and minimum. 76 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Iruma, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan19.4 C (66.9 F)-9.4 C (15.1 F)14.0 C (57.2 F)-4.0 C (24.8 F)
Feb21.7 C (71.1 F)-6.1 C (21.0 F)17.0 C (62.6 F)-4.0 C (24.8 F)
Mar26.7 C (80.1 F)-6.7 C (19.9 F)25.0 C (77.0 F)-2.0 C (28.4 F)
Apr29.4 C (84.9 F)-1.1 C (30.0 F)25.0 C (77.0 F)4.0 C (39.2 F)
May32.8 C (91.0 F)2.8 C (37.0 F)29.0 C (84.2 F)13.0 C (55.4 F)
Jun35.6 C (96.1 F)9.4 C (48.9 F)35.0 C (95.0 F)13.0 C (55.4 F)
Jul37.0 C (98.6 F)15.0 C (59.0 F)37.0 C (98.6 F)20.0 C (68.0 F)
Aug40.0 C (104.0 F)14.4 C (57.9 F)40.0 C (104.0 F)23.0 C (73.4 F)
Sep35.0 C (95.0 F)8.9 C (48.0 F)35.0 C (95.0 F)17.0 C (62.6 F)
Oct27.8 C (82.0 F)3.9 C (39.0 F)27.0 C (80.6 F)9.0 C (48.2 F)
Nov22.8 C (73.0 F)-3.3 C (26.1 F)22.0 C (71.6 F)2.0 C (35.6 F)
Dec20.6 C (69.1 F)-7.2 C (19.0 F)20.0 C (68.0 F)-3.0 C (26.6 F)

Which Years Hold Standing Records

1,464 standing records
Standing records at Iruma by the year they were set 1,464 records at Iruma still stand. 2025 holds the most, with 183. 0501001502001949: 1331950: 871951: 1211952: 961953: 1051954: 1381955: 871956: 1141957: 1041958: 1211959: 901960: 852025: 1831949195119531955195719592025
1,464 records at Iruma still stand. 2025 holds the most, with 183.
Standing records at Iruma by the year they were set
Year setStanding records
1949133
195087
1951121
195296
1953105
1954138
195587
1956114
1957104
1958121
195990
196085
2025183

Wettest Day of Each Month

Sep: 235.7 mm (9.3 in)
Record daily precipitation for each month at Iruma The wettest day on record for each calendar month at Iruma. The most was 235.7 mm (9.3 in) on 26 September 1958. 0100200300 Jan: 48.8 mm (1.9 in), 31 January 1950 Jan Feb: 97.3 mm (3.8 in), 7 February 1955 Feb Mar: 55.1 mm (2.2 in), 19 March 1956 Mar Apr: 73.7 mm (2.9 in), 1 April 1950 Apr May: 75.4 mm (3.0 in), 20 May 1957 May Jun: 100.6 mm (4.0 in), 19 June 1949 Jun Jul: 149.4 mm (5.9 in), 28 July 1950 Jul Aug: 168.1 mm (6.6 in), 11 August 1960 Aug Sep: 235.7 mm (9.3 in), 26 September 1958 Sep Oct: 101.3 mm (4.0 in), 11 October 1955 Oct Nov: 89.2 mm (3.5 in), 21 November 1955 Nov Dec: 57.4 mm (2.3 in), 3 December 1959 Dec
The wettest day on record for each calendar month at Iruma. The most was 235.7 mm (9.3 in) on 26 September 1958.
Record daily precipitation for each month at Iruma
MonthRecord daily precipitation (mm)Date
Jan48.8 mm (1.9 in)31 January 1950
Feb97.3 mm (3.8 in)7 February 1955
Mar55.1 mm (2.2 in)19 March 1956
Apr73.7 mm (2.9 in)1 April 1950
May75.4 mm (3.0 in)20 May 1957
Jun100.6 mm (4.0 in)19 June 1949
Jul149.4 mm (5.9 in)28 July 1950
Aug168.1 mm (6.6 in)11 August 1960
Sep235.7 mm (9.3 in)26 September 1958
Oct101.3 mm (4.0 in)11 October 1955
Nov89.2 mm (3.5 in)21 November 1955
Dec57.4 mm (2.3 in)3 December 1959

Period of Record Coverage

1949 to 2025
Days with data per year at Iruma 13 years of record at Iruma, 1949 to 2025. 1 years have data for under 90 percent of days and are left out of rankings: 2025. 1949: 365 of 365 days1950: 355 of 365 days1951: 365 of 365 days1952: 366 of 366 days1953: 365 of 365 days1954: 365 of 365 days1955: 365 of 365 days1956: 366 of 366 days1957: 365 of 365 days1958: 365 of 365 days1959: 365 of 365 days1960: 366 of 366 days2025: 293 of 365 days1950195519602025
13 years of record at Iruma, 1949 to 2025. 1 years have data for under 90 percent of days and are left out of rankings: 2025.
Days with data per year at Iruma
YearDays with dataShare of yearComplete
1949365100%Yes
195035597%Yes
1951365100%Yes
1952366100%Yes
1953365100%Yes
1954365100%Yes
1955365100%Yes
1956366100%Yes
1957365100%Yes
1958365100%Yes
1959365100%Yes
1960366100%Yes
202529380%No

Latest Records

0

No records were set at this station in the latest data.

Climate Trend

12 complete years, 1949 to 1960
Annual mean temperature at Iruma as warming stripes, 1949 to 1960 One stripe for each of 12 complete years at Iruma, 1949 to 1960. Blue stripes are years cooler than the station's own mean of 14.3 C (57.7 F); red stripes are warmer. The coolest year was 1953, at 14.0 C (57.1 F), and the warmest was 1955, at 15.0 C (58.9 F). The strongest colour marks a difference of 0.7 C (1.3 F). 1949: 14.2 C, -0.1 C from the station mean1950: 14.7 C, +0.4 C from the station mean1951: 14.4 C, +0.1 C from the station mean1952: 14.3 C, 0.0 C from the station mean1953: 14.0 C, -0.3 C from the station mean1954: 14.2 C, -0.1 C from the station mean1955: 15.0 C, +0.7 C from the station mean1956: 14.1 C, -0.2 C from the station mean1957: 14.0 C, -0.3 C from the station mean1958: 14.1 C, -0.2 C from the station mean1959: 14.5 C, +0.2 C from the station mean1960: 14.2 C, -0.1 C from the station mean1949195019521954195619581960
One stripe for each of 12 complete years at Iruma, 1949 to 1960. Blue stripes are years cooler than the station's own mean of 14.3 C (57.7 F); red stripes are warmer. The coolest year was 1953, at 14.0 C (57.1 F), and the warmest was 1955, at 15.0 C (58.9 F). The strongest colour marks a difference of 0.7 C (1.3 F).
Annual mean temperature at Iruma as warming stripes, 1949 to 1960
YearAnnual mean temperatureDifference from the station mean
194914.2 C-0.12 C
195014.7 C+0.36 C
195114.4 C+0.10 C
195214.3 C-0.03 C
195314.0 C-0.35 C
195414.2 C-0.12 C
195515.0 C+0.66 C
195614.1 C-0.16 C
195714.0 C-0.33 C
195814.1 C-0.16 C
195914.5 C+0.18 C
196014.2 C-0.08 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

1949 to 2026
Yearly extremes at Iruma: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)40.0 C (104.0 F)202536.1 C (97.0 F)14
Coldest night (TNn)-9.4 C (15.1 F)1960-6.1 C (21.0 F)14
Wettest day (Rx1day)235.7 mm (9.3 in)1958121.1 mm (4.8 in)12
Wettest five days (Rx5day)414.3 mm (16.3 in)1950177.9 mm (7.0 in)12
Longest dry spell (CDD)33 days195122 days12

Hottest day (TXx)

Hottest day (TXx) at Iruma by year The hottest day of the year at Iruma, 1949 to 2026. The record is 40.0 C (104.0 F) in 2025, marked on the chart; the median year is 36.1 C (97.0 F). 102030401960198020002020Record: 40.0 C (104.0 F) in 2025
The hottest day of the year at Iruma, 1949 to 2026. The record is 40.0 C (104.0 F) in 2025, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Iruma by year
YearHottest day (TXx)
194935.6 C (96.1 F)
195036.1 C (97.0 F)
195137.2 C (99.0 F)
195236.1 C (97.0 F)
195336.1 C (97.0 F)
195435.0 C (95.0 F)
195536.1 C (97.0 F)
195636.1 C (97.0 F)
195734.4 C (93.9 F)
195836.1 C (97.0 F)
195935.0 C (95.0 F)
196034.4 C (93.9 F)
202540.0 C (104.0 F)
202618.0 C (64.4 F)

Coldest night (TNn)

Coldest night (TNn) at Iruma by year The coldest night of the year at Iruma, 1949 to 2026. The record is -9.4 C (15.1 F) in 1960, marked on the chart; the median year is -6.1 C (21.0 F). -10-8-6-41960198020002020Record: -9.4 C (15.1 F) in 1960
The coldest night of the year at Iruma, 1949 to 2026. The record is -9.4 C (15.1 F) in 1960, marked on the chart; the median year is -6.1 C (21.0 F).
Coldest night (TNn) at Iruma by year
YearColdest night (TNn)
1949-6.7 C (19.9 F)
1950-5.6 C (21.9 F)
1951-6.7 C (19.9 F)
1952-6.1 C (21.0 F)
1953-5.6 C (21.9 F)
1954-7.8 C (18.0 F)
1955-6.1 C (21.0 F)
1956-6.1 C (21.0 F)
1957-6.1 C (21.0 F)
1958-7.2 C (19.0 F)
1959-7.2 C (19.0 F)
1960-9.4 C (15.1 F)
2025-4.0 C (24.8 F)
2026-6.0 C (21.2 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Iruma by year The wettest day of the year at Iruma, 1949 to 2026. The record is 235.7 mm (9.3 in) in 1958, marked on the chart; the median year is 121.1 mm (4.8 in). 501001502002501960198020002020Record: 235.7 mm (9.3 in) in 1958
The wettest day of the year at Iruma, 1949 to 2026. The record is 235.7 mm (9.3 in) in 1958, marked on the chart; the median year is 121.1 mm (4.8 in).
Wettest day (Rx1day) at Iruma by year
YearWettest day (Rx1day)
1949125.7 mm (4.9 in)
1950149.4 mm (5.9 in)
1951117.6 mm (4.6 in)
195283.3 mm (3.3 in)
1953124.5 mm (4.9 in)
1954168.1 mm (6.6 in)
1955101.3 mm (4.0 in)
195676.5 mm (3.0 in)
195775.9 mm (3.0 in)
1958235.7 mm (9.3 in)
195990.7 mm (3.6 in)
1960168.1 mm (6.6 in)
2025n/a
2026n/a

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Iruma by year The wettest five days of the year at Iruma, 1949 to 2026. The record is 414.3 mm (16.3 in) in 1950, marked on the chart; the median year is 177.9 mm (7.0 in). 1002003004005001960198020002020Record: 414.3 mm (16.3 in) in 1950
The wettest five days of the year at Iruma, 1949 to 2026. The record is 414.3 mm (16.3 in) in 1950, marked on the chart; the median year is 177.9 mm (7.0 in).
Wettest five days (Rx5day) at Iruma by year
YearWettest five days (Rx5day)
1949163.9 mm (6.5 in)
1950414.3 mm (16.3 in)
1951162.1 mm (6.4 in)
1952191.8 mm (7.6 in)
1953219.7 mm (8.6 in)
1954258.8 mm (10.2 in)
1955125.2 mm (4.9 in)
1956124.2 mm (4.9 in)
1957119.9 mm (4.7 in)
1958302.7 mm (11.9 in)
1959152.6 mm (6.0 in)
1960238.7 mm (9.4 in)
2025n/a
2026n/a

Longest dry spell (CDD)

Longest dry spell (CDD) at Iruma by year The longest dry spell of the year at Iruma, 1949 to 2026. The record is 33 days in 1951, marked on the chart; the median year is 22 days. 15202530351960198020002020Record: 33 days in 1951
The longest dry spell of the year at Iruma, 1949 to 2026. The record is 33 days in 1951, marked on the chart; the median year is 22 days.
Longest dry spell (CDD) at Iruma by year
YearLongest dry spell (CDD)
194930 days
195019 days
195133 days
195218 days
195317 days
195420 days
195523 days
195623 days
195733 days
195815 days
195921 days
196025 days
2025n/a
2026n/a

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.

Download the Data

  • Data for Iruma standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Iruma 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 (2025-12-31).