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Helena 1 SSE Weather Records (USC00344019)

Record envelope, standing records and threshold days for Helena 1 SSE (USC00344019), Oklahoma, United States, with 121 years of record.

Key Facts for Helena 1 SSE

  • Helena 1 SSE (USC00344019) is a weather station in Oklahoma, United States at 36.54 latitude and -98.27 longitude, 412 m (1,350 ft) above sea level.
  • The station reports from 1906 to 2026, 121 years of record.
  • 1,464 records set at Helena 1 SSE still stand.
  • Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
  • Helena 1 SSE tied a daily record high maximum temperature of 37.8 C (100.0 F) on 19 September 2026 (provisional).

Provisional Records

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

About the Station

  • Location: Oklahoma, United States, 36.54 latitude, -98.27 longitude.
  • Elevation: 412 m (1,350 ft).
  • Period of record: 1906 to 2026, 121 years.
  • Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

17 days at or beyond a record
Daily record high and record low at Helena 1 SSE, with 2026 drawn through them The band shows the record high and record low for each calendar day at Helena 1 SSE. The lines show the 2026 daily maximum and minimum. 17 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. -40-200204060 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Helena 1 SSE. The lines show the 2026 daily maximum and minimum. 17 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Helena 1 SSE, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan27.8 C (82.0 F)-25.6 C (-14.1 F)21.7 C (71.1 F)-17.2 C (1.0 F)
Feb33.3 C (91.9 F)-29.4 C (-20.9 F)26.7 C (80.1 F)-11.1 C (12.0 F)
Mar37.2 C (99.0 F)-18.3 C (-0.9 F)36.7 C (98.1 F)-7.2 C (19.0 F)
Apr37.2 C (99.0 F)-7.8 C (18.0 F)32.2 C (90.0 F)2.8 C (37.0 F)
May40.6 C (105.1 F)-1.7 C (28.9 F)35.0 C (95.0 F)5.6 C (42.1 F)
Jun45.0 C (113.0 F)7.8 C (46.0 F)38.3 C (100.9 F)15.6 C (60.1 F)
Jul45.0 C (113.0 F)10.0 C (50.0 F)41.7 C (107.1 F)17.2 C (63.0 F)
Aug44.4 C (111.9 F)8.9 C (48.0 F)42.2 C (108.0 F)16.7 C (62.1 F)
Sep42.2 C (108.0 F)-0.6 C (30.9 F)41.1 C (106.0 F)15.6 C (60.1 F)
Oct36.7 C (98.1 F)-11.1 C (12.0 F)33.3 C (91.9 F)11.1 C (52.0 F)
Nov32.8 C (91.0 F)-15.0 C (5.0 F)n/an/a
Dec26.7 C (80.1 F)-26.1 C (-15.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Helena 1 SSE by the year they were set 1,464 records at Helena 1 SSE still stand. 1911 holds the most, with 47. 02040601906: 211907: 251908: 71910: 371911: 471912: 281913: 331914: 91944: 61961: 191962: 281963: 231964: 211965: 171966: 281967: 231968: 161969: 151970: 241971: 201972: 251973: 91974: 231975: 201976: 131977: 61978: 261979: 201980: 211981: 211982: 171983: 341984: 191985: 221986: 151987: 71988: 141989: 311990: 151991: 161992: 101993: 171994: 131995: 161996: 271997: 131998: 211999: 102000: 212001: 102002: 112003: 212004: 112005: 182006: 322007: 132008: 112009: 202010: 22011: 422012: 212013: 232014: 312015: 192016: 152017: 92018: 192019: 142020: 162021: 242022: 242023: 162024: 242025: 182026: 311906194419681976198419922000200820162024
1,464 records at Helena 1 SSE still stand. 1911 holds the most, with 47.
Standing records at Helena 1 SSE by the year they were set
Year setStanding records
190621
190725
19087
191037
191147
191228
191333
19149
19446
196119
196228
196323
196421
196517
196628
196723
196816
196915
197024
197120
197225
19739
197423
197520
197613
19776
197826
197920
198021
198121
198217
198334
198419
198522
198615
19877
198814
198931
199015
199116
199210
199317
199413
199516
199627
199713
199821
199910
200021
200110
200211
200321
200411
200518
200632
200713
200811
200920
20102
201142
201221
201323
201431
201519
201615
20179
201819
201914
202016
202124
202224
202316
202424
202518
202631

All-Time Record Progression

3 new records
When Helena 1 SSE set new all-time records 3 all-time records were set at Helena 1 SSE between 19 July 1997 and 10 February 2011. Each dot is a new record. Record daily precipitationRecord low minimum temperature19 July 1997: Record daily precipitation 166.4 mm (6.6 in)12 September 2008: Record daily precipitation 222.0 mm (8.7 in)10 February 2011: Record low minimum temperature -29.4 C (-20.9 F)200020052010
3 all-time records were set at Helena 1 SSE between 19 July 1997 and 10 February 2011. Each dot is a new record.
When Helena 1 SSE set new all-time records
DateKindDetail
1997-07-19Record daily precipitationRecord daily precipitation 166.4 mm (6.6 in)
2008-09-12Record daily precipitationRecord daily precipitation 222.0 mm (8.7 in)
2011-02-10Record low minimum temperatureRecord low minimum temperature -29.4 C (-20.9 F)

Wettest Day of Each Month

Sep: 222.0 mm (8.7 in)
Record daily precipitation for each month at Helena 1 SSE The wettest day on record for each calendar month at Helena 1 SSE. The most was 222.0 mm (8.7 in) on 12 September 2008. 0100200300 Jan: 68.3 mm (2.7 in), 5 January 2005 Jan Feb: 64.8 mm (2.6 in), 21 February 1997 Feb Mar: 124.5 mm (4.9 in), 3 March 1988 Mar Apr: 180.8 mm (7.1 in), 26 April 2009 Apr May: 115.8 mm (4.6 in), 21 May 2019 May Jun: 138.4 mm (5.4 in), 23 June 1963 Jun Jul: 166.4 mm (6.6 in), 19 July 1997 Jul Aug: 84.8 mm (3.3 in), 3 August 1995 Aug Sep: 222.0 mm (8.7 in), 12 September 2008 Sep Oct: 127.0 mm (5.0 in), 3 October 1986 Oct Nov: 104.1 mm (4.1 in), 3 November 1974 Nov Dec: 73.7 mm (2.9 in), 4 December 1947 Dec
The wettest day on record for each calendar month at Helena 1 SSE. The most was 222.0 mm (8.7 in) on 12 September 2008.
Record daily precipitation for each month at Helena 1 SSE
MonthRecord daily precipitation (mm)Date
Jan68.3 mm (2.7 in)5 January 2005
Feb64.8 mm (2.6 in)21 February 1997
Mar124.5 mm (4.9 in)3 March 1988
Apr180.8 mm (7.1 in)26 April 2009
May115.8 mm (4.6 in)21 May 2019
Jun138.4 mm (5.4 in)23 June 1963
Jul166.4 mm (6.6 in)19 July 1997
Aug84.8 mm (3.3 in)3 August 1995
Sep222.0 mm (8.7 in)12 September 2008
Oct127.0 mm (5.0 in)3 October 1986
Nov104.1 mm (4.1 in)3 November 1974
Dec73.7 mm (2.9 in)4 December 1947

Period of Record Coverage

1906 to 2026
Days with data per year at Helena 1 SSE 75 years of record at Helena 1 SSE, 1906 to 2026. 9 years have data for under 90 percent of days and are left out of rankings: 1906, 1907, 1908, 1912, 1913, 1914, 1944, 1961 and others. 1906: 234 of 365 days1907: 235 of 365 days1908: 73 of 366 days1910: 341 of 365 days1911: 363 of 365 days1912: 328 of 366 days1913: 272 of 365 days1914: 213 of 365 days1944: 80 of 366 days1961: 267 of 365 days1962: 356 of 365 days1963: 359 of 365 days1964: 346 of 366 days1965: 364 of 365 days1966: 364 of 365 days1967: 363 of 365 days1968: 365 of 366 days1969: 365 of 365 days1970: 365 of 365 days1971: 364 of 365 days1972: 366 of 366 days1973: 364 of 365 days1974: 340 of 365 days1975: 365 of 365 days1976: 365 of 366 days1977: 364 of 365 days1978: 364 of 365 days1979: 364 of 365 days1980: 366 of 366 days1981: 365 of 365 days1982: 362 of 365 days1983: 365 of 365 days1984: 366 of 366 days1985: 364 of 365 days1986: 365 of 365 days1987: 365 of 365 days1988: 364 of 366 days1989: 364 of 365 days1990: 365 of 365 days1991: 363 of 365 days1992: 366 of 366 days1993: 365 of 365 days1994: 364 of 365 days1995: 364 of 365 days1996: 366 of 366 days1997: 364 of 365 days1998: 364 of 365 days1999: 365 of 365 days2000: 365 of 366 days2001: 365 of 365 days2002: 363 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: 364 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: 364 of 365 days2023: 361 of 365 days2024: 366 of 366 days2025: 364 of 365 days2026: 280 of 365 days1910197019801990200020102020
75 years of record at Helena 1 SSE, 1906 to 2026. 9 years have data for under 90 percent of days and are left out of rankings: 1906, 1907, 1908, 1912, 1913, 1914, 1944, 1961 and others.
Days with data per year at Helena 1 SSE
YearDays with dataShare of yearComplete
190623464%No
190723564%No
19087320%No
191034193%Yes
191136399%Yes
191232890%No
191327275%No
191421358%No
19448022%No
196126773%No
196235698%Yes
196335998%Yes
196434695%Yes
1965364100%Yes
1966364100%Yes
196736399%Yes
1968365100%Yes
1969365100%Yes
1970365100%Yes
1971364100%Yes
1972366100%Yes
1973364100%Yes
197434093%Yes
1975365100%Yes
1976365100%Yes
1977364100%Yes
1978364100%Yes
1979364100%Yes
1980366100%Yes
1981365100%Yes
198236299%Yes
1983365100%Yes
1984366100%Yes
1985364100%Yes
1986365100%Yes
1987365100%Yes
198836499%Yes
1989364100%Yes
1990365100%Yes
199136399%Yes
1992366100%Yes
1993365100%Yes
1994364100%Yes
1995364100%Yes
1996366100%Yes
1997364100%Yes
1998364100%Yes
1999365100%Yes
2000365100%Yes
2001365100%Yes
200236399%Yes
2003365100%Yes
2004366100%Yes
2005365100%Yes
2006365100%Yes
2007365100%Yes
2008366100%Yes
2009365100%Yes
2010365100%Yes
2011365100%Yes
2012366100%Yes
2013365100%Yes
2014364100%Yes
2015365100%Yes
2016366100%Yes
2017365100%Yes
2018365100%Yes
2019365100%Yes
2020366100%Yes
2021365100%Yes
2022364100%Yes
202336199%Yes
2024366100%Yes
2025364100%Yes
202628077%No

Latest Records

20
Latest records at Helena 1 SSE
DateStationRecordValueBeat old record byOld record stoodSignificance
19 September 2026Helena 1 SSE, USdaily high max (Tie, Provisional)37.8 C (100.0 F)tie116 years10 of 100 (Routine)
19 September 2026Helena 1 SSE, USdaily high min (Tie, Provisional)24.4 C (75.9 F)tie28 years4 of 100 (Routine)
18 September 2026Helena 1 SSE, USdaily high max (Provisional)38.9 C (102.0 F)1.7 C (3.1 F)116 years43 of 100 (Notable)
18 September 2026Helena 1 SSE, USdaily high min (Tie, Provisional)24.4 C (75.9 F)tie11 years3 of 100 (Routine)
16 September 2026Helena 1 SSE, USdaily high max (Tie, Provisional)38.9 C (102.0 F)tie48 years6 of 100 (Routine)
15 September 2026Helena 1 SSE, USdaily high min (Provisional)25.6 C (78.1 F)2.3 C (4.1 F)115 years45 of 100 (Notable)
13 September 2026Helena 1 SSE, USdaily high max (Provisional)39.4 C (102.9 F)1.6 C (2.9 F)15 years16 of 100 (Routine)
10 September 2026Helena 1 SSE, USdaily high max (Provisional)41.1 C (106.0 F)2.8 C (5.0 F)56 years31 of 100 (Routine)
9 September 2026Helena 1 SSE, USmonthly high min (Tie, Provisional)26.7 C (80.1 F)tie46 years8 of 100 (Routine)
9 September 2026Helena 1 SSE, USdaily high max (Tie, Provisional)39.4 C (102.9 F)tie40 years5 of 100 (Routine)
8 September 2026Helena 1 SSE, USmonthly high min (Tie, Provisional)26.7 C (80.1 F)tie46 years8 of 100 (Routine)
5 September 2026Helena 1 SSE, USdaily high min (Provisional)25.6 C (78.1 F)0.6 C (1.1 F)3 years11 of 100 (Routine)
4 September 2026Helena 1 SSE, USdaily high min (Tie, Provisional)23.3 C (73.9 F)tie113 years10 of 100 (Routine)
3 September 2026Helena 1 SSE, USdaily high min (Tie, Provisional)25.0 C (77.0 F)tie4 years2 of 100 (Routine)
2 September 2026Helena 1 SSE, USdaily high min (Provisional)25.6 C (78.1 F)2.3 C (4.1 F)113 years45 of 100 (Notable)
31 August 2026Helena 1 SSE, USdaily high min (Provisional)25.0 C (77.0 F)0.6 C (1.1 F)15 years16 of 100 (Routine)
30 August 2026Helena 1 SSE, USdaily high min (Provisional)25.0 C (77.0 F)1.1 C (2.0 F)113 years43 of 100 (Notable)
22 August 2026Helena 1 SSE, USdaily high min (Provisional)25.0 C (77.0 F)0.6 C (1.1 F)24 years19 of 100 (Routine)
21 August 2026Helena 1 SSE, USdaily high min (Tie, Provisional)24.4 C (75.9 F)tie23 years4 of 100 (Routine)
16 August 2026Helena 1 SSE, USdaily high min (Provisional)25.0 C (77.0 F)0.6 C (1.1 F)0 years12 of 100 (Routine)

Climate Trend

63 complete years, 1911 to 2025
Annual mean temperature at Helena 1 SSE as warming stripes, 1911 to 2025 One stripe for each of 63 complete years at Helena 1 SSE, 1911 to 2025. Blue stripes are years cooler than the station's own mean of 14.6 C (58.2 F); red stripes are warmer. The coolest year was 1979, at 13.0 C (55.4 F), and the warmest was 2024, at 16.8 C (62.2 F). The strongest colour marks a difference of 2.3 C (4.1 F). 1911: 15.9 C, +1.3 C from the station mean1962: 14.8 C, +0.3 C from the station mean1963: 15.4 C, +0.8 C from the station mean1964: 14.5 C, 0.0 C from the station mean1965: 14.8 C, +0.2 C from the station mean1966: 13.6 C, -1.0 C from the station mean1967: 13.9 C, -0.6 C from the station mean1968: 13.5 C, -1.1 C from the station mean1969: 13.9 C, -0.7 C from the station mean1970: 14.1 C, -0.5 C from the station mean1971: 14.1 C, -0.4 C from the station mean1972: 13.8 C, -0.8 C from the station mean1973: 14.1 C, -0.4 C from the station mean1975: 13.3 C, -1.2 C from the station mean1977: 14.7 C, +0.1 C from the station mean1978: 13.4 C, -1.2 C from the station mean1979: 13.0 C, -1.6 C from the station mean1980: 15.0 C, +0.4 C from the station mean1981: 15.4 C, +0.8 C from the station mean1982: 13.8 C, -0.8 C from the station mean1983: 13.6 C, -1.0 C from the station mean1984: 14.4 C, -0.1 C from the station mean1985: 13.9 C, -0.7 C from the station mean1986: 15.4 C, +0.8 C from the station mean1987: 14.5 C, 0.0 C from the station mean1988: 13.9 C, -0.7 C from the station mean1989: 13.2 C, -1.3 C from the station mean1990: 14.8 C, +0.2 C from the station mean1991: 15.0 C, +0.4 C from the station mean1992: 14.5 C, -0.1 C from the station mean1993: 13.2 C, -1.4 C from the station mean1994: 14.9 C, +0.4 C from the station mean1995: 14.2 C, -0.4 C from the station mean1996: 14.1 C, -0.5 C from the station mean1997: 14.3 C, -0.3 C from the station mean1998: 16.1 C, +1.6 C from the station mean1999: 15.1 C, +0.5 C from the station mean2000: 14.5 C, 0.0 C from the station mean2001: 15.4 C, +0.8 C from the station mean2002: 14.2 C, -0.4 C from the station mean2003: 14.3 C, -0.3 C from the station mean2004: 14.6 C, +0.1 C from the station mean2005: 14.9 C, +0.3 C from the station mean2006: 15.9 C, +1.4 C from the station mean2007: 14.6 C, 0.0 C from the station mean2008: 14.1 C, -0.5 C from the station mean2009: 14.1 C, -0.5 C from the station mean2010: 14.6 C, 0.0 C from the station mean2011: 15.2 C, +0.6 C from the station mean2012: 16.2 C, +1.6 C from the station mean2013: 13.4 C, -1.1 C from the station mean2014: 13.7 C, -0.8 C from the station mean2015: 14.9 C, +0.4 C from the station mean2016: 15.8 C, +1.2 C from the station mean2017: 15.4 C, +0.8 C from the station mean2018: 14.7 C, +0.1 C from the station mean2019: 14.4 C, -0.2 C from the station mean2020: 14.8 C, +0.3 C from the station mean2021: 15.2 C, +0.7 C from the station mean2022: 15.0 C, +0.4 C from the station mean2023: 15.7 C, +1.1 C from the station mean2024: 16.8 C, +2.2 C from the station mean2025: 15.3 C, +0.8 C from the station mean191119201930194019501960197019801990200020102020
One stripe for each of 63 complete years at Helena 1 SSE, 1911 to 2025. Blue stripes are years cooler than the station's own mean of 14.6 C (58.2 F); red stripes are warmer. The coolest year was 1979, at 13.0 C (55.4 F), and the warmest was 2024, at 16.8 C (62.2 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Helena 1 SSE as warming stripes, 1911 to 2025
YearAnnual mean temperatureDifference from the station mean
191115.9 C+1.33 C
196214.8 C+0.26 C
196315.4 C+0.82 C
196414.5 C-0.05 C
196514.8 C+0.19 C
196613.6 C-0.97 C
196713.9 C-0.63 C
196813.5 C-1.06 C
196913.9 C-0.67 C
197014.1 C-0.50 C
197114.1 C-0.43 C
197213.8 C-0.79 C
197314.1 C-0.42 C
197513.3 C-1.24 C
197714.7 C+0.11 C
197813.4 C-1.21 C
197913.0 C-1.58 C
198015.0 C+0.39 C
198115.4 C+0.80 C
198213.8 C-0.80 C
198313.6 C-0.98 C
198414.4 C-0.14 C
198513.9 C-0.68 C
198615.4 C+0.79 C
198714.5 C-0.04 C
198813.9 C-0.68 C
198913.2 C-1.33 C
199014.8 C+0.23 C
199115.0 C+0.40 C
199214.5 C-0.10 C
199313.2 C-1.38 C
199414.9 C+0.38 C
199514.2 C-0.36 C
199614.1 C-0.47 C
199714.3 C-0.31 C
199816.1 C+1.56 C
199915.1 C+0.52 C
200014.5 C-0.02 C
200115.4 C+0.81 C
200214.2 C-0.41 C
200314.3 C-0.29 C
200414.6 C+0.06 C
200514.9 C+0.32 C
200615.9 C+1.35 C
200714.6 C+0.01 C
200814.1 C-0.48 C
200914.1 C-0.48 C
201014.6 C+0.01 C
201115.2 C+0.64 C
201216.2 C+1.61 C
201313.4 C-1.12 C
201413.7 C-0.82 C
201514.9 C+0.35 C
201615.8 C+1.22 C
201715.4 C+0.81 C
201814.7 C+0.10 C
201914.4 C-0.19 C
202014.8 C+0.25 C
202115.2 C+0.65 C
202215.0 C+0.39 C
202315.7 C+1.11 C
202416.8 C+2.23 C
202515.3 C+0.75 C

The annual mean temperature here has risen by 0.11 C (0.01 to 0.20) per decade over 1911 to 2025. In Fahrenheit: 0.19 F (0.02 to 0.36) per decade. The slope is a straight line fitted to 63 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Helena 1 SSE
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.11 C (0.01 to 0.20) per decade0.19 F (0.02 to 0.36) per decade1911 to 202563Rise
Mean daily maximum0.12 C (0.01 to 0.23) per decade0.22 F (0.03 to 0.42) per decade1911 to 202563Rise
Mean daily minimum0.09 C (-0.01 to 0.18) per decade0.15 F (-0.02 to 0.32) per decade1911 to 202563Not clearly different from zero

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

1906 to 2026
Yearly extremes at Helena 1 SSE: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)45.0 C (113.0 F)191141.1 C (106.0 F)75
Coldest night (TNn)-29.4 C (-20.9 F)2011-17.8 C (0.0 F)75
Wettest day (Rx1day)222.0 mm (8.7 in)200869.8 mm (2.7 in)94
Wettest five days (Rx5day)252.7 mm (9.9 in)200895.4 mm (3.8 in)94
Longest dry spell (CDD)113 days191035 days94

Hottest day (TXx)

Hottest day (TXx) at Helena 1 SSE by year The hottest day of the year at Helena 1 SSE, 1906 to 2026. The record is 45.0 C (113.0 F) in 1911, marked on the chart; the median year is 41.1 C (106.0 F). 30354045192019401960198020002020Record: 45.0 C (113.0 F) in 1911
The hottest day of the year at Helena 1 SSE, 1906 to 2026. The record is 45.0 C (113.0 F) in 1911, marked on the chart; the median year is 41.1 C (106.0 F).
Hottest day (TXx) at Helena 1 SSE by year
YearHottest day (TXx)
190634.4 C (93.9 F)
190737.8 C (100.0 F)
190833.9 C (93.0 F)
191042.8 C (109.0 F)
191145.0 C (113.0 F)
191241.1 C (106.0 F)
191341.7 C (107.1 F)
191441.1 C (106.0 F)
1941n/a
1942n/a
1943n/a
194435.0 C (95.0 F)
1945n/a
1946n/a
1947n/a
1948n/a
1949n/a
1950n/a
1951n/a
1952n/a
1953n/a
1954n/a
1955n/a
1956n/a
1957n/a
1958n/a
1959n/a
1960n/a
196139.4 C (102.9 F)
196242.2 C (108.0 F)
196341.1 C (106.0 F)
196444.4 C (111.9 F)
196539.4 C (102.9 F)
196641.1 C (106.0 F)
196740.0 C (104.0 F)
196841.1 C (106.0 F)
196942.8 C (109.0 F)
197042.2 C (108.0 F)
197143.3 C (109.9 F)
197238.9 C (102.0 F)
197341.7 C (107.1 F)
197443.9 C (111.0 F)
197538.9 C (102.0 F)
197641.7 C (107.1 F)
197740.0 C (104.0 F)
197842.2 C (108.0 F)
197940.0 C (104.0 F)
198044.4 C (111.9 F)
198142.8 C (109.0 F)
198241.1 C (106.0 F)
198341.7 C (107.1 F)
198442.2 C (108.0 F)
198542.2 C (108.0 F)
198645.0 C (113.0 F)
198739.4 C (102.9 F)
198841.1 C (106.0 F)
198938.9 C (102.0 F)
199041.7 C (107.1 F)
199141.1 C (106.0 F)
199238.3 C (100.9 F)
199339.4 C (102.9 F)
199441.7 C (107.1 F)
199541.1 C (106.0 F)
199642.2 C (108.0 F)
199738.9 C (102.0 F)
199841.7 C (107.1 F)
199940.6 C (105.1 F)
200042.2 C (108.0 F)
200142.2 C (108.0 F)
200239.4 C (102.9 F)
200341.7 C (107.1 F)
200439.4 C (102.9 F)
200539.4 C (102.9 F)
200642.8 C (109.0 F)
200738.9 C (102.0 F)
200841.1 C (106.0 F)
200943.9 C (111.0 F)
201041.1 C (106.0 F)
201144.4 C (111.9 F)
201243.9 C (111.0 F)
201341.1 C (106.0 F)
201439.4 C (102.9 F)
201539.4 C (102.9 F)
201641.1 C (106.0 F)
201741.1 C (106.0 F)
201843.3 C (109.9 F)
201941.1 C (106.0 F)
202040.0 C (104.0 F)
202139.4 C (102.9 F)
202244.4 C (111.9 F)
202342.2 C (108.0 F)
202442.8 C (109.0 F)
202539.4 C (102.9 F)
202642.2 C (108.0 F)

Coldest night (TNn)

Coldest night (TNn) at Helena 1 SSE by year The coldest night of the year at Helena 1 SSE, 1906 to 2026. The record is -29.4 C (-20.9 F) in 2011, marked on the chart; the median year is -17.8 C (0.0 F). -30-20-100192019401960198020002020Record: -29.4 C (-20.9 F) in 2011
The coldest night of the year at Helena 1 SSE, 1906 to 2026. The record is -29.4 C (-20.9 F) in 2011, marked on the chart; the median year is -17.8 C (0.0 F).
Coldest night (TNn) at Helena 1 SSE by year
YearColdest night (TNn)
1906-17.2 C (1.0 F)
1907-14.4 C (6.1 F)
1908-12.8 C (9.0 F)
1910-15.0 C (5.0 F)
1911-24.4 C (-11.9 F)
1912-24.4 C (-11.9 F)
1913-21.7 C (-7.1 F)
1914-17.8 C (0.0 F)
1941n/a
1942n/a
1943n/a
1944-2.8 C (27.0 F)
1945n/a
1946n/a
1947n/a
1948n/a
1949n/a
1950n/a
1951n/a
1952n/a
1953n/a
1954n/a
1955n/a
1956n/a
1957n/a
1958n/a
1959n/a
1960n/a
1961-18.3 C (-0.9 F)
1962-19.4 C (-2.9 F)
1963-21.1 C (-6.0 F)
1964-17.2 C (1.0 F)
1965-16.1 C (3.0 F)
1966-18.3 C (-0.9 F)
1967-17.2 C (1.0 F)
1968-18.9 C (-2.0 F)
1969-17.2 C (1.0 F)
1970-17.2 C (1.0 F)
1971-16.1 C (3.0 F)
1972-20.6 C (-5.1 F)
1973-20.0 C (-4.0 F)
1974-17.2 C (1.0 F)
1975-17.8 C (0.0 F)
1976-17.8 C (0.0 F)
1977-19.4 C (-2.9 F)
1978-19.4 C (-2.9 F)
1979-22.8 C (-9.0 F)
1980-14.4 C (6.1 F)
1981-22.2 C (-8.0 F)
1982-26.1 C (-15.0 F)
1983-20.0 C (-4.0 F)
1984-25.0 C (-13.0 F)
1985-18.9 C (-2.0 F)
1986-15.0 C (5.0 F)
1987-18.9 C (-2.0 F)
1988-25.6 C (-14.1 F)
1989-26.1 C (-15.0 F)
1990-18.9 C (-2.0 F)
1991-17.2 C (1.0 F)
1992-10.6 C (12.9 F)
1993-16.7 C (1.9 F)
1994-17.2 C (1.0 F)
1995-13.9 C (7.0 F)
1996-22.8 C (-9.0 F)
1997-16.7 C (1.9 F)
1998-19.4 C (-2.9 F)
1999-13.9 C (7.0 F)
2000-17.2 C (1.0 F)
2001-12.8 C (9.0 F)
2002-17.8 C (0.0 F)
2003-17.8 C (0.0 F)
2004-16.7 C (1.9 F)
2005-17.8 C (0.0 F)
2006-13.9 C (7.0 F)
2007-18.9 C (-2.0 F)
2008-15.0 C (5.0 F)
2009-17.2 C (1.0 F)
2010-17.2 C (1.0 F)
2011-29.4 C (-20.9 F)
2012-12.8 C (9.0 F)
2013-16.7 C (1.9 F)
2014-21.1 C (-6.0 F)
2015-13.9 C (7.0 F)
2016-19.4 C (-2.9 F)
2017-16.7 C (1.9 F)
2018-18.9 C (-2.0 F)
2019-13.9 C (7.0 F)
2020-12.2 C (10.0 F)
2021-25.0 C (-13.0 F)
2022-18.9 C (-2.0 F)
2023-11.7 C (10.9 F)
2024-17.2 C (1.0 F)
2025-23.3 C (-9.9 F)
2026-17.2 C (1.0 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Helena 1 SSE by year The wettest day of the year at Helena 1 SSE, 1906 to 2026. The record is 222.0 mm (8.7 in) in 2008, marked on the chart; the median year is 69.8 mm (2.7 in). 050100150200250192019401960198020002020Record: 222.0 mm (8.7 in) in 2008
The wettest day of the year at Helena 1 SSE, 1906 to 2026. The record is 222.0 mm (8.7 in) in 2008, marked on the chart; the median year is 69.8 mm (2.7 in).
Wettest day (Rx1day) at Helena 1 SSE by year
YearWettest day (Rx1day)
190640.6 mm (1.6 in)
190763.5 mm (2.5 in)
190850.8 mm (2.0 in)
191064.8 mm (2.6 in)
191165.5 mm (2.6 in)
191230.5 mm (1.2 in)
191366.0 mm (2.6 in)
191430.5 mm (1.2 in)
194161.5 mm (2.4 in)
194227.2 mm (1.1 in)
194372.4 mm (2.9 in)
194471.1 mm (2.8 in)
194590.4 mm (3.6 in)
194640.9 mm (1.6 in)
194773.7 mm (2.9 in)
194883.8 mm (3.3 in)
194987.6 mm (3.4 in)
195075.4 mm (3.0 in)
195197.5 mm (3.8 in)
195232.0 mm (1.3 in)
195343.4 mm (1.7 in)
195459.4 mm (2.3 in)
195567.6 mm (2.7 in)
195632.3 mm (1.3 in)
1957101.6 mm (4.0 in)
195858.4 mm (2.3 in)
195982.8 mm (3.3 in)
1960111.0 mm (4.4 in)
196159.7 mm (2.4 in)
196232.3 mm (1.3 in)
1963138.4 mm (5.4 in)
196487.4 mm (3.4 in)
196557.4 mm (2.3 in)
196634.0 mm (1.3 in)
196795.3 mm (3.8 in)
196836.3 mm (1.4 in)
196950.8 mm (2.0 in)
197077.0 mm (3.0 in)
197190.4 mm (3.6 in)
197262.0 mm (2.4 in)
197386.6 mm (3.4 in)
1974104.1 mm (4.1 in)
197537.6 mm (1.5 in)
197633.8 mm (1.3 in)
197780.3 mm (3.2 in)
197849.8 mm (2.0 in)
1979104.4 mm (4.1 in)
198058.4 mm (2.3 in)
198183.1 mm (3.3 in)
198292.7 mm (3.6 in)
198349.3 mm (1.9 in)
198449.5 mm (1.9 in)
198543.4 mm (1.7 in)
1986127.0 mm (5.0 in)
198786.4 mm (3.4 in)
1988124.5 mm (4.9 in)
198978.7 mm (3.1 in)
199038.1 mm (1.5 in)
199149.0 mm (1.9 in)
199263.8 mm (2.5 in)
199376.2 mm (3.0 in)
199480.0 mm (3.1 in)
199584.8 mm (3.3 in)
199655.4 mm (2.2 in)
1997166.4 mm (6.6 in)
199893.5 mm (3.7 in)
199975.2 mm (3.0 in)
200063.5 mm (2.5 in)
200141.4 mm (1.6 in)
2002100.6 mm (4.0 in)
200365.0 mm (2.6 in)
200478.2 mm (3.1 in)
200571.4 mm (2.8 in)
200653.1 mm (2.1 in)
200757.2 mm (2.3 in)
2008222.0 mm (8.7 in)
2009180.8 mm (7.1 in)
201084.6 mm (3.3 in)
201148.0 mm (1.9 in)
2012100.3 mm (3.9 in)
201372.9 mm (2.9 in)
201470.4 mm (2.8 in)
201587.4 mm (3.4 in)
2016111.8 mm (4.4 in)
201780.8 mm (3.2 in)
201869.1 mm (2.7 in)
2019115.8 mm (4.6 in)
202060.7 mm (2.4 in)
202149.0 mm (1.9 in)
202262.5 mm (2.5 in)
202347.0 mm (1.9 in)
202479.8 mm (3.1 in)
202585.9 mm (3.4 in)
202638.4 mm (1.5 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Helena 1 SSE by year The wettest five days of the year at Helena 1 SSE, 1906 to 2026. The record is 252.7 mm (9.9 in) in 2008, marked on the chart; the median year is 95.4 mm (3.8 in). 0100200300192019401960198020002020Record: 252.7 mm (9.9 in) in 2008
The wettest five days of the year at Helena 1 SSE, 1906 to 2026. The record is 252.7 mm (9.9 in) in 2008, marked on the chart; the median year is 95.4 mm (3.8 in).
Wettest five days (Rx5day) at Helena 1 SSE by year
YearWettest five days (Rx5day)
190675.4 mm (3.0 in)
1907114.3 mm (4.5 in)
190827.9 mm (1.1 in)
191064.8 mm (2.6 in)
1911139.0 mm (5.5 in)
191252.8 mm (2.1 in)
191376.2 mm (3.0 in)
191440.6 mm (1.6 in)
194178.5 mm (3.1 in)
194243.2 mm (1.7 in)
194391.0 mm (3.6 in)
194471.1 mm (2.8 in)
1945126.7 mm (5.0 in)
194672.1 mm (2.8 in)
1947105.0 mm (4.1 in)
194893.5 mm (3.7 in)
1949152.9 mm (6.0 in)
1950138.9 mm (5.5 in)
1951171.1 mm (6.7 in)
195260.8 mm (2.4 in)
195380.8 mm (3.2 in)
195467.2 mm (2.6 in)
1955128.6 mm (5.1 in)
195637.9 mm (1.5 in)
1957123.9 mm (4.9 in)
195871.9 mm (2.8 in)
1959158.0 mm (6.2 in)
1960167.4 mm (6.6 in)
196186.1 mm (3.4 in)
196273.5 mm (2.9 in)
1963148.6 mm (5.9 in)
1964124.8 mm (4.9 in)
1965155.4 mm (6.1 in)
196645.4 mm (1.8 in)
1967116.5 mm (4.6 in)
196864.3 mm (2.5 in)
196971.9 mm (2.8 in)
197093.5 mm (3.7 in)
197195.7 mm (3.8 in)
197277.2 mm (3.0 in)
1973106.0 mm (4.2 in)
1974135.4 mm (5.3 in)
197579.8 mm (3.1 in)
197663.8 mm (2.5 in)
1977128.5 mm (5.1 in)
197895.0 mm (3.7 in)
1979108.2 mm (4.3 in)
198095.2 mm (3.7 in)
1981103.2 mm (4.1 in)
1982129.1 mm (5.1 in)
198384.4 mm (3.3 in)
198454.6 mm (2.1 in)
198574.4 mm (2.9 in)
1986227.3 mm (8.9 in)
1987126.8 mm (5.0 in)
1988153.0 mm (6.0 in)
1989137.2 mm (5.4 in)
199051.5 mm (2.0 in)
199170.4 mm (2.8 in)
1992109.5 mm (4.3 in)
1993127.9 mm (5.0 in)
199492.4 mm (3.6 in)
1995141.7 mm (5.6 in)
199696.5 mm (3.8 in)
1997171.0 mm (6.7 in)
1998193.8 mm (7.6 in)
1999102.1 mm (4.0 in)
200085.1 mm (3.4 in)
200163.2 mm (2.5 in)
2002122.4 mm (4.8 in)
200378.4 mm (3.1 in)
2004107.2 mm (4.2 in)
2005117.6 mm (4.6 in)
200669.9 mm (2.8 in)
2007117.9 mm (4.6 in)
2008252.7 mm (9.9 in)
2009190.5 mm (7.5 in)
201095.5 mm (3.8 in)
201156.2 mm (2.2 in)
2012137.9 mm (5.4 in)
201394.0 mm (3.7 in)
201484.6 mm (3.3 in)
2015114.3 mm (4.5 in)
2016141.5 mm (5.6 in)
201790.2 mm (3.6 in)
2018156.0 mm (6.1 in)
2019152.9 mm (6.0 in)
2020130.1 mm (5.1 in)
202158.4 mm (2.3 in)
202286.3 mm (3.4 in)
202377.8 mm (3.1 in)
202485.4 mm (3.4 in)
2025118.2 mm (4.7 in)
202651.8 mm (2.0 in)

Longest dry spell (CDD)

Longest dry spell (CDD) at Helena 1 SSE by year The longest dry spell of the year at Helena 1 SSE, 1906 to 2026. The record is 113 days in 1910, marked on the chart; the median year is 35 days. 0255075100125192019401960198020002020Record: 113 days in 1910
The longest dry spell of the year at Helena 1 SSE, 1906 to 2026. The record is 113 days in 1910, marked on the chart; the median year is 35 days.
Longest dry spell (CDD) at Helena 1 SSE by year
YearLongest dry spell (CDD)
190630 days
190738 days
190838 days
1910113 days
191133 days
191250 days
191324 days
191443 days
194117 days
194230 days
194316 days
194423 days
194549 days
194624 days
194739 days
194842 days
194950 days
195058 days
195130 days
195253 days
195337 days
195451 days
195557 days
195640 days
195734 days
195821 days
195939 days
196019 days
196122 days
196228 days
196357 days
196436 days
196543 days
196669 days
196725 days
196822 days
196928 days
197056 days
197154 days
197237 days
197335 days
197427 days
197541 days
197664 days
197736 days
197840 days
197938 days
198028 days
198122 days
198232 days
198352 days
198422 days
198524 days
198638 days
198730 days
198842 days
198962 days
199037 days
199141 days
199220 days
199321 days
199425 days
199538 days
199640 days
199725 days
199833 days
199923 days
200036 days
200129 days
200235 days
200338 days
200424 days
200543 days
200655 days
200731 days
200828 days
200926 days
201028 days
201128 days
201233 days
201328 days
201429 days
201530 days
201635 days
201737 days
201847 days
201928 days
202027 days
202158 days
202242 days
202330 days
202437 days
202536 days
202626 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

63 years with a frost

Across 63 years with a frost, the median last spring frost at Helena 1 SSE falls on 10 April and the median first autumn frost on 29 October, which leaves a median of 201 days between them.

In 1996 to 2025 the median growing season was 206 days. That is 5 days more than in 1911 to 1992.

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

Frost dates and growing season at Helena 1 SSE
MeasureMedian, all yearsEarliest period (1911 to 1992)Recent period (1996 to 2025)Recent against earliestFitted trend
Last spring frost10 April7 April11 April4 days later+0.1 days per decade
First autumn frost29 October29 October30 October1 day later+0.8 days per decade
Growing days201 days201 days206 days5 days more+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

82 years, 1910 to 2025

A day with at least 70.1 mm (2.8 in) of rain is expected about once in 2 years. A day with at least 180.7 mm (7.1 in) of rain is expected about once in 100 years.

Rainfall return levels at Helena 1 SSE: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years70.1 mm (2.8 in)
5 years98.5 mm (3.9 in)
10 years117.7 mm (4.6 in)
25 years142.7 mm (5.6 in)
50 years161.6 mm (6.4 in)
100 years180.7 mm (7.1 in)Longer than the 82 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, 82 years of values from 1910 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: 222.0 mm (8.7 in) in 2008; 180.8 mm (7.1 in) in 2009; 166.4 mm (6.6 in) in 1997.

Station Changes

1 suspected

One change was suspected in the annual mean temperature of Helena 1 SSE, at 2009. Each is measured against neighbouring stations.

  • Relative to 5 neighbouring stations, the station's annual mean temperature from 2009 ran 0.2 C (0.4 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Helena 1 SSE, against neighbouring stations
YearShift (C)Shift (F)StrengthNeighbours
2009-0.2-0.4possible5

Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.

Climate Twins

2011 to 2025 against 1961 to 1990

Over 2011 to 2025, Helena 1 SSE had a mean temperature of 15.1 C (59.2 F) and 763.9 mm (30.1 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Buffalo 2 SSW (United States, 126 km away), Boxian (China, 11,426 km away) and Geary (United States, 101 km away).

Climate twins of Helena 1 SSE: stations whose 1961 to 1990 climate is closest to its 2011 to 2025 climate
Twin stationCountryDistance awayMean temperature, 1961-1990Rain a year, 1961-1990Climate difference
Buffalo 2 SSWUnited States126 km (78 mi)15.2 C (59.3 F)709.8 mm (27.9 in)0.82
BoxianChina11,426 km (7,100 mi)15.0 C (59.0 F)802.3 mm (31.6 in)0.91
GearyUnited States101 km (63 mi)15.4 C (59.7 F)713.2 mm (28.1 in)0.91

Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.

Download the Data

  • Data for Helena 1 SSE standing records by year: CSV or JSON. Field meanings are on the data page.
  • Data for Helena 1 SSE 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.

Data as of . Last revised (2026-10-13).