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Data as of 2026-10-17
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Built 2026-10-19 (19 October 2026)

Heat wave in Japan and 5 other countries, 12 to 24 May 2021

Heat wave in Japan and 5 other countries, 12 to 24 May 2021: 302 records at 168 stations, peak on 16 May 2021. Closed.

Data as of . Last revised (2026-10-17).

Key Facts

  • Heat wave in Japan and 5 other countries, 12 to 24 May 2021 set or tied 302 station records at 168 stations.
  • It ran from 12 May 2021 to 24 May 2021 (13 days) and its peak day was 16 May 2021.
  • Status: closed.
  • Mokpo set a daily record high minimum temperature of 19.5 C (67.1 F) on 15 May 2021.
  • The busiest day was 16 May 2021 with 51 records.
  • The oldest broken record in the ranked list had stood for 83 years.

Footprint

12 to 24 May 2021
Footprint of Heat wave in Japan and 5 other countries, 12 to 24 May 2021 The area covered by Heat wave in Japan and 5 other countries, 12 to 24 May 2021 is outlined, with 20 of the stations that set records marked, coloured by record type.
The area covered by Heat wave in Japan and 5 other countries, 12 to 24 May 2021 is outlined, with 20 of the stations that set records marked, coloured by record type. Made with Natural Earth.
Footprint of Heat wave in Japan and 5 other countries, 12 to 24 May 2021: stations that set records in the event
StationTypeValueDate
MokpoRecord high minimum temperature19.5 C (67.1 F)2021-05-15
KawaguchikoRecord high minimum temperature16.8 C (62.2 F)2021-05-17
KofuRecord high minimum temperature21.1 C (70.0 F)2021-05-18
SagaRecord high minimum temperature22.3 C (72.1 F)2021-05-16
IlyinskiyRecord high maximum temperature20.8 C (69.4 F)2021-05-17
MatsuyamaRecord high minimum temperature19.4 C (66.9 F)2021-05-14
IzuharaRecord high minimum temperature18.5 C (65.3 F)2021-05-15
IizukaRecord high minimum temperature22.5 C (72.5 F)2021-05-16
UshibukaRecord high minimum temperature22.0 C (71.6 F)2021-05-16
IrozakiRecord high minimum temperature20.1 C (68.2 F)2021-05-18
PogranichnoeRecord high maximum temperature26.3 C (79.3 F)2021-05-18
PosetRecord high minimum temperature10.9 C (51.6 F)2021-05-15
TadotsuRecord high minimum temperature19.1 C (66.4 F)2021-05-17
FukuokaRecord high minimum temperature21.3 C (70.3 F)2021-05-15
HitaRecord high minimum temperature21.0 C (69.8 F)2021-05-16
NazeRecord high minimum temperature25.6 C (78.1 F)2021-05-20
HamamatsuRecord high minimum temperature20.1 C (68.2 F)2021-05-18
TongheRecord high minimum temperature16.4 C (61.5 F)2021-05-20
ShizuokaRecord high minimum temperature18.9 C (66.0 F)2021-05-20
EsashiRecord high minimum temperature13.6 C (56.5 F)2021-05-21

Records per Day

Peak day 51
Records per day during Heat wave in Japan and 5 other countries, 12 to 24 May 2021 Records set or tied each day from 12 May 2021 to 24 May 2021. The most in one day was 51 on 16 May 2021. 0 15 30 45 60 05-1205-1405-1605-1805-2005-2205-24
Records set or tied each day from 12 May 2021 to 24 May 2021. The most in one day was 51 on 16 May 2021.
Records per day during Heat wave in Japan and 5 other countries, 12 to 24 May 2021
DateRecords
2021-05-123
2021-05-137
2021-05-1424
2021-05-1535
2021-05-1651
2021-05-1732
2021-05-1842
2021-05-1911
2021-05-2024
2021-05-2113
2021-05-2231
2021-05-2324
2021-05-245

Top Records by Margin

Margin over the record replaced
Top records of Heat wave in Japan and 5 other countries, 12 to 24 May 2021 ranked by margin
Iizuka, 05-164.2 C (7.6 F)
Kawaguchiko, 05-173.6 C (6.5 F)
Saga, 05-163.0 C (5.4 F)
Pogranichnoe, 05-182.8 C (5.0 F)
Tonghe, 05-202.8 C (5.0 F)
Fukuoka, 05-152.7 C (4.9 F)
Mokpo, 05-152.5 C (4.5 F)
Ilyinskiy, 05-172.5 C (4.5 F)
Hita, 05-162.5 C (4.5 F)
Ushibuka, 05-162.1 C (3.8 F)
Matsuyama, 05-142.0 C (3.6 F)
Irozaki, 05-182.0 C (3.6 F)
Naze, 05-201.7 C (3.1 F)
Izuhara, 05-151.6 C (2.9 F)
Esashi, 05-211.6 C (2.9 F)

Margin is how far the new value is beyond the record it replaced. Ties are not shown.

Margin Against Age of the Broken Record

Margin against age of the broken record in Heat wave in Japan and 5 other countries, 12 to 24 May 2021 302 records plotted by how far they beat the old record (across) and how many years the old record had stood (up). Long standing records beaten by a wide margin sit in the top right. 0 25 50 75 100 0.01.32.53.85.0 Margin (C) Years the old record stood
302 records plotted by how far they beat the old record (across) and how many years the old record had stood (up). Long standing records beaten by a wide margin sit in the top right.
Margin against age of the broken record in Heat wave in Japan and 5 other countries, 12 to 24 May 2021
Margin (C)Years the old record stood
2.583
3.670
0.660
3.060
2.572
1.670
4.252
2.160
2.067
2.054
2.872
1.270
0.476
2.752
2.560
1.760
2.856
1.659
1.458
0.968
1.658
2.458
1.560
1.562
2.652
1.258
2.152
1.060
1.958
0.966
1.458
0.170
0.368
1.458
0.567
2.052
1.547
0.668
1.060
2.444
1.458
1.848
0.268
0.268
1.258
0.960
1.358
1.160
1.752
1.258
0.267
1.552
0.958
0.463
1.452
1.748
1.158
1.352
1.058
1.452
0.658
0.267
1.252
0.858
0.660
1.543
0.362
0.659
0.856
2.144
1.448
0.558
0.654
0.160
0.260
1.052
1.852
0.458
0.658
0.358
2.044
3.339
3.142
0.555
0.655
1.146
0.652
0.752
0.358
0.752
0.558
0.458
0.555
0.459
1.347
2.736
0.255
0.258
1.340
0.254
0.258
0.552
0.848
3.142
0.944
1.148
1.940
0.847
1.632
0.152
0.352
0.252
0.844
0.547
0.552
0.252
0.116
1.630
2.823
2.042
0.348
1.643
3.92
1.642
0.940
0.743
0.940
0.344
1.039
0.247
0.844
1.536
1.936
1.631
1.723
1.642
0.244
0.540
1.924
0.647
0.836
0.942
0.430
0.442
0.140
0.240
1.130
1.523
0.147
1.823
1.030
0.244
3.018
1.919
0.440
3.83
0.136
0.231
2.918
0.830
0.724
1.124
0.336
0.24
0.632
2.911
0.327
0.724
0.624
1.116
0.527
0.527
0.724
0.724
1.612
0.432
0.728
2.218
2.612
3.12
1.222
2.90
0.423
0.816
1.516
0.723
0.130
1.122
1.318
3.73
1.78
0.231
0.716
0.819
1.516
0.423
0.524
0.816
0.524
2.43

Compared With Other Events

Station records per event
Station records in Heat wave in Japan and 5 other countries, 12 to 24 May 2021 compared with similar events
Heat wave in United States and Mexico, 16 January to 14 February 20249,869 records
Heat wave in United States, 28 January to 24 February 20266,528 records
Heat wave in United States and Mexico, 24 May to 19 June 20205,047 records
Heat wave in United States and Mexico, 26 March to 17 April 20213,669 records
Heat wave in Germany and 49 other countries, 18 December 2021 to 15 January 20223,626 records
Heat wave in Japan and 5 other countries, 12 to 24 May 2021 (this event)302 records

Every Record Set

20 of 302
Every record set or tied during Heat wave in Japan and 5 other countries, 12 to 24 May 2021, in date order
DateStationRecordValueMarginYears stoodSignificance
2021-05-14MatsuyamaRecord high minimum temperature19.4 C (66.9 F)2.0 C (3.6 F)6734 of 100 (Routine)
2021-05-15MokpoRecord high minimum temperature19.5 C (67.1 F)2.5 C (4.5 F)8343 of 100 (Notable)
2021-05-15IzuharaRecord high minimum temperature18.5 C (65.3 F)1.6 C (2.9 F)7034 of 100 (Routine)
2021-05-15PosetRecord high minimum temperature10.9 C (51.6 F)0.4 C (0.7 F)7632 of 100 (Routine)
2021-05-15FukuokaRecord high minimum temperature21.3 C (70.3 F)2.7 C (4.9 F)5231 of 100 (Routine)
2021-05-16SagaRecord high minimum temperature22.3 C (72.1 F)3.0 C (5.4 F)6035 of 100 (Notable)
2021-05-16IizukaRecord high minimum temperature22.5 C (72.5 F)4.2 C (7.6 F)5234 of 100 (Routine)
2021-05-16UshibukaRecord high minimum temperature22.0 C (71.6 F)2.1 C (3.8 F)6034 of 100 (Routine)
2021-05-16HitaRecord high minimum temperature21.0 C (69.8 F)2.5 C (4.5 F)6031 of 100 (Routine)
2021-05-17KawaguchikoRecord high minimum temperature16.8 C (62.2 F)3.6 C (6.5 F)7039 of 100 (Notable)
2021-05-17IlyinskiyRecord high maximum temperature20.8 C (69.4 F)2.5 C (4.5 F)7235 of 100 (Notable)
2021-05-17TadotsuRecord high minimum temperature19.1 C (66.4 F)1.2 C (2.2 F)7032 of 100 (Routine)
2021-05-18KofuRecord high minimum temperature21.1 C (70.0 F)0.6 C (1.1 F)6036 of 100 (Notable)
2021-05-18IrozakiRecord high minimum temperature20.1 C (68.2 F)2.0 C (3.6 F)5433 of 100 (Routine)
2021-05-18PogranichnoeRecord high maximum temperature26.3 C (79.3 F)2.8 C (5.0 F)7233 of 100 (Routine)
2021-05-18HamamatsuRecord high minimum temperature20.1 C (68.2 F)1.4 C (2.5 F)5830 of 100 (Routine)
2021-05-20NazeRecord high minimum temperature25.6 C (78.1 F)1.7 C (3.1 F)6031 of 100 (Routine)
2021-05-20TongheRecord high minimum temperature16.4 C (61.5 F)2.8 C (5.0 F)5630 of 100 (Routine)
2021-05-20ShizuokaRecord high minimum temperature18.9 C (66.0 F)0.9 C (1.6 F)6830 of 100 (Routine)
2021-05-21EsashiRecord high minimum temperature13.6 C (56.5 F)1.6 C (2.9 F)5930 of 100 (Routine)

The daily ledgers keep a limited number of records per day, so this list has 20 of the 302 records the event counts. The counts above use the full total.

Download the Data

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. Events are found by this site from station records and are not official designations. Records are provisional until reprocessed.