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Built 2026-10-17 (17 October 2026)

Weather Records on 21 September 1917

28 weather records were set or tied worldwide on 21 September 1917. Highest significance: Bologna, IT.

Key Facts for 21 September 1917

  • On 21 September 1917, 28 weather records were set or tied at long-record stations worldwide.
  • 10 were record highs and 1 were record lows, counting maximum and minimum temperature.
  • By timescale, 0 were all-time records, 2 monthly and 26 daily.
  • Bologna set a daily record high minimum temperature of 20.8 C (69.4 F) on 21 September 1917.
  • Across 155 earlier years (1805 to 2026) the same calendar date averaged 454 records.

Record Map

28 stations
Weather records on 21 September 1917 28 station records on 21 September 1917 are marked on the map, coloured by record type.
28 station records on 21 September 1917 are marked on the map, coloured by record type. Dot size shows the significance score. Made with Natural Earth.
Weather records on 21 September 1917: highest significance records shown on the map
StationCountryTypeValueSignificance
BolognaItalyRecord high minimum temperature20.8 C (69.4 F)34 of 100 (Routine)
GoglandRussiaRecord daily precipitation37.9 mm (1.5 in)24 of 100 (Routine)
Cape Borda ComparisonAustraliaRecord daily precipitation13.7 mm (0.5 in)20 of 100 (Routine)
BredasdorpSouth AfricaRecord daily precipitation21.1 mm (0.8 in)20 of 100 (Routine)
Munchen-NymphenburgGermanyRecord high minimum temperature15.1 C (59.2 F)19 of 100 (Routine)
Zagreb-GricCroatiaRecord high maximum temperature28.1 C (82.6 F)19 of 100 (Routine)
EkaterinburgRussiaRecord daily precipitation35.3 mm (1.4 in)19 of 100 (Routine)
Holmogadd ASwedenRecord daily precipitation15.8 mm (0.6 in)19 of 100 (Routine)
Lake Victoria (Cal-Lal)AustraliaRecord daily precipitation8.4 mm (0.33 in)16 of 100 (Routine)
NurnbergGermanyRecord high minimum temperature14.1 C (57.4 F)15 of 100 (Routine)
Gunnedah PoolAustraliaRecord low maximum temperature17.8 C (64.0 F)14 of 100 (Routine)
BindiAustraliaRecord daily precipitation19.1 mm (0.8 in)14 of 100 (Routine)
TobolskRussiaRecord daily precipitation7.2 mm (0.28 in)14 of 100 (Routine)
KremsmuensterAustriaRecord high minimum temperature15.7 C (60.3 F)13 of 100 (Routine)
Atlantic City MarinaUnited StatesRecord daily precipitation10.2 mm (0.4 in)13 of 100 (Routine)
Binya (Merribee)AustraliaRecord daily precipitation4.3 mm (0.17 in)12 of 100 (Routine)
The OlivesAustraliaRecord daily precipitation16.5 mm (0.6 in)12 of 100 (Routine)
Swift CurrentCanadaRecord high maximum temperature31.7 C (89.1 F)12 of 100 (Routine)
KingscoteAustraliaRecord daily precipitation7.6 mm (0.30 in)11 of 100 (Routine)
TareenaAustraliaRecord daily precipitation4.6 mm (0.18 in)10 of 100 (Routine)
Merrowie NorthAustraliaRecord daily precipitation6.6 mm (0.26 in)10 of 100 (Routine)
Prince AlbertCanadaRecord high maximum temperature30.0 C (86.0 F)10 of 100 (Routine)
Mount MacedonAustraliaRecord daily precipitation28.4 mm (1.1 in)9 of 100 (Routine)
GorkiBelarusRecord daily precipitation9.3 mm (0.37 in)9 of 100 (Routine)
Calgary Int'l ACanadaRecord high maximum temperature26.7 C (80.1 F)8 of 100 (Routine)
Corny Point LighthouseAustraliaRecord daily precipitation8.9 mm (0.35 in)7 of 100 (Routine)
WienAustriaRecord high minimum temperature15.9 C (60.6 F)3 of 100 (Routine)
HohenpeissenbergGermanyRecord high maximum temperature20.3 C (68.5 F)3 of 100 (Routine)

Counts by Type and Timescale

28 records
Records on 21 September 1917 by type Records set or tied on 21 September 1917 by type: Highest daily maximum 5, Lowest daily maximum 1, Highest daily minimum 5, Heaviest daily rainfall 17. 05101520Highest daily maximum: 5Lowest daily maximum: 1Highest daily minimum: 5Lowest daily minimum: 0Heaviest daily rainfall: 17Heaviest daily snowfall: 0Deepest snow cover: 0Max highMax lowMin highMin lowRainSnowDepth
Records set or tied on 21 September 1917 by type: Highest daily maximum 5, Lowest daily maximum 1, Highest daily minimum 5, Heaviest daily rainfall 17.
Records on 21 September 1917 by type
Record typeRecords
Highest daily maximum5
Lowest daily maximum1
Highest daily minimum5
Lowest daily minimum0
Heaviest daily rainfall17
Heaviest daily snowfall0
Deepest snow cover0
Records on 21 September 1917 by timescale Records on 21 September 1917 by timescale: all-time 0, monthly 2, daily 26. 0102030all-time: 0monthly: 2daily: 26all-timemonthlydaily
Records on 21 September 1917 by timescale: all-time 0, monthly 2, daily 26.
Records on 21 September 1917 by timescale
TimescaleRecords
all-time0
monthly2
daily26

How Much Records Were Beaten By

26 broken records
Histogram of margins by which records were beaten on 21 September 1917 Margins by which the 26 broken records beat the old ones, in degrees Celsius for temperature and millimetres for precipitation and snow; the largest margin was 9.7. Ties are not counted. 0510150 to 2: 142 to 4: 74 to 6: 36 to 8: 18 to 10: 10 to 22 to 44 to 66 to 88 to 10
Margins by which the 26 broken records beat the old ones, in degrees Celsius for temperature and millimetres for precipitation and snow; the largest margin was 9.7. Ties are not counted.
Histogram of margins by which records were beaten on 21 September 1917
MarginRecords
0 to 214
2 to 47
4 to 63
6 to 81
8 to 101

Top 20 by Significance

21 September 1917
Top 20 records on 21 September 1917 by significance
DateStationRecordValueBeat old record byOld record stoodSignificance
21 September 1917Bologna, ITdaily high min20.8 C (69.4 F)0.2 C (0.4 F)82 years34 of 100 (Routine)
21 September 1917Gogland, RUmonthly rain37.9 mm (1.5 in)0.7 mm (0.03 in)34 years24 of 100 (Routine)
21 September 1917Cape Borda Comparison, AUdaily rain13.7 mm (0.5 in)5.1 mm (0.20 in)16 years20 of 100 (Routine)
21 September 1917Bredasdorp, ZAdaily rain21.1 mm (0.8 in)9.7 mm (0.38 in)12 years20 of 100 (Routine)
21 September 1917Munchen-Nymphenburg, DEdaily high min15.1 C (59.2 F)1.9 C (3.4 F)37 years19 of 100 (Routine)
21 September 1917Zagreb-Gric, HRdaily high max28.1 C (82.6 F)3.1 C (5.6 F)31 years19 of 100 (Routine)
21 September 1917Ekaterinburg, RUmonthly rain35.3 mm (1.4 in)1.8 mm (0.07 in)9 years19 of 100 (Routine)
21 September 1917Holmogadd A, SEdaily rain15.8 mm (0.6 in)5.4 mm (0.21 in)27 years19 of 100 (Routine)
21 September 1917Lake Victoria (Cal-Lal), AUdaily rain8.4 mm (0.33 in)2.8 mm (0.11 in)31 years16 of 100 (Routine)
21 September 1917Nurnberg, DEdaily high min14.1 C (57.4 F)0.5 C (0.9 F)37 years15 of 100 (Routine)
21 September 1917Gunnedah Pool, AUdaily low max17.8 C (64.0 F)2.8 C (5.0 F)12 years14 of 100 (Routine)
21 September 1917Bindi, AUdaily rain19.1 mm (0.8 in)7.7 mm (0.30 in)8 years14 of 100 (Routine)
21 September 1917Tobolsk, RUdaily rain7.2 mm (0.28 in)1.1 mm (0.04 in)31 years14 of 100 (Routine)
21 September 1917Kremsmuenster, ATdaily high min15.7 C (60.3 F)1.5 C (2.7 F)16 years13 of 100 (Routine)
21 September 1917Atlantic City Marina, USdaily rain10.2 mm (0.4 in)1.6 mm (0.06 in)28 years13 of 100 (Routine)
21 September 1917Binya (Merribee), AUdaily rain4.3 mm (0.17 in)1.3 mm (0.05 in)28 years12 of 100 (Routine)
21 September 1917The Olives, AUdaily rain16.5 mm (0.6 in)2.0 mm (0.08 in)25 years12 of 100 (Routine)
21 September 1917Swift Current, CAdaily high max31.7 C (89.1 F)2.8 C (5.0 F)19 years12 of 100 (Routine)
21 September 1917Kingscote, AUdaily rain7.6 mm (0.30 in)2.5 mm (0.10 in)8 years11 of 100 (Routine)
21 September 1917Tareena, AUdaily rain4.6 mm (0.18 in)1.6 mm (0.06 in)16 years10 of 100 (Routine)

Significance is a score from 0 to 100 combining margin, the age of the old record and the length of the station's record. How it is computed.

The Same Date in Other Years

1805 to 1917
Records on 09-21 in each year Records set or tied on this calendar date in each year from 1805 to 1917. 1917 had 28 records. 01,0002,0003,0001805: 11812: 11825: 21840: 11841: 11842: 11848: 11854: 11856: 21868: 11872: 21873: 11877: 11878: 11881: 11882: 11884: 11886: 11888: 21889: 11891: 101892: 11893: 101894: 21895: 31896: 21897: 61898: 61899: 31900: 21901: 51902: 51903: 81904: 201905: 121906: 171907: 101908: 171909: 101910: 81911: 181912: 261913: 371914: 291915: 341916: 481917: 281918: 431919: 541920: 291921: 641922: 351923: 2321924: 2911925: 2781926: 1781927: 1651928: 811929: 2321930: 821931: 6811932: 2421933: 1931934: 4921935: 1991936: 3291937: 4871938: 5081939: 3081940: 9081941: 4161942: 2911943: 4071944: 4131945: 5071946: 1761947: 5341948: 3011949: 2981950: 3341951: 2411952: 4301953: 3821954: 4531955: 7521956: 1,1001957: 3661958: 5881959: 5131960: 4181961: 4411962: 1,0851963: 3061964: 3741965: 1,0881966: 5651967: 5771968: 7901969: 5931970: 7081971: 6451972: 5991973: 4211974: 6521975: 5281976: 6941977: 9181978: 8181979: 7361980: 9901981: 6961982: 1,4841983: 2,2071984: 7071985: 7961986: 6711987: 9651988: 5571989: 1,0021990: 7161991: 1,0211992: 7521993: 9111994: 7131995: 2,0021996: 1,2331997: 1,1121998: 1,4811999: 1,0252000: 8842001: 7182002: 6962003: 9592004: 8882005: 1,1432006: 9202007: 7422008: 7402009: 7152010: 1,2902011: 5422012: 5952013: 7692014: 7162015: 5652016: 9892017: 1,1782018: 1,0512019: 8332020: 5802021: 4652022: 1,0492023: 7832024: 4702025: 5912026: 4781805188419031919193519511967198319992015
Records set or tied on this calendar date in each year from 1805 to 1917. 1917 had 28 records.
Counts for years before the ledger starts come from the same station rules.
Records on 09-21 in each year
YearRecords
18051
18121
18252
18401
18411
18421
18481
18541
18562
18681
18722
18731
18771
18781
18811
18821
18841
18861
18882
18891
189110
18921
189310
18942
18953
18962
18976
18986
18993
19002
19015
19025
19038
190420
190512
190617
190710
190817
190910
19108
191118
191226
191337
191429
191534
191648
191728
191843
191954
192029
192164
192235
1923232
1924291
1925278
1926178
1927165
192881
1929232
193082
1931681
1932242
1933193
1934492
1935199
1936329
1937487
1938508
1939308
1940908
1941416
1942291
1943407
1944413
1945507
1946176
1947534
1948301
1949298
1950334
1951241
1952430
1953382
1954453
1955752
19561,100
1957366
1958588
1959513
1960418
1961441
19621,085
1963306
1964374
19651,088
1966565
1967577
1968790
1969593
1970708
1971645
1972599
1973421
1974652
1975528
1976694
1977918
1978818
1979736
1980990
1981696
19821,484
19832,207
1984707
1985796
1986671
1987965
1988557
19891,002
1990716
19911,021
1992752
1993911
1994713
19952,002
19961,233
19971,112
19981,481
19991,025
2000884
2001718
2002696
2003959
2004888
20051,143
2006920
2007742
2008740
2009715
20101,290
2011542
2012595
2013769
2014716
2015565
2016989
20171,178
20181,051
2019833
2020580
2021465
20221,049
2023783
2024470
2025591
2026478

Download the Data

  • Data for records on 1917-09-21: CSV or JSON. Field meanings are on the data page.

Sources: 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)) Made with Natural Earth. Public domain map data. Borders are Natural Earth's de facto depiction. Data as of 2026-10-14 (14 October 2026). Records are computed by this site and are not official.

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