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

Rocky Boy Threshold Days by Year (USS0009A01S)

12 fixed thresholds counted per year at Rocky Boy (USS0009A01S): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Rocky Boy Thresholds

  • Rocky Boy: days with a maximum temperature at or below 0 C (32 F) in 30 years, most in 2019 with 71.
  • Rocky Boy: nights with a minimum temperature at or below 0 C (32 F) in 30 years, most in 2000 with 228.
  • Rocky Boy: nights with a minimum temperature at or below -10 C (14 F) in 30 years, most in 2000 with 90.
  • Rocky Boy: nights with a minimum temperature at or below -20 C (-4 F) in 30 years, most in 2019 with 38.
  • 12 fixed thresholds have at least one qualifying day at Rocky Boy.
29 years with a qualifying day
Days at or above 30 C (86 F) per year at Rocky Boy Days per year at Rocky Boy with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 22 in 2021. 01020301998: 41999: 22000: 72001: 62002: 62003: 152004: 22005: 62006: 92007: 122008: 62009: 32010: 22011: 32012: 192013: 62014: 42015: 132016: 52017: 202018: 122019: 62020: 82021: 222022: 172023: 122024: 132025: 22026: 51998200120042007201020132016201920222025
Days per year at Rocky Boy with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 22 in 2021.
Days at or above 30 C (86 F) per year at Rocky Boy
YearDaysDecade average
199843
199923
200077.2
200167.2
200267.2
2003157.2
200427.2
200567.2
200697.2
2007127.2
200867.2
200937.2
201029
201139
2012199
201369
201449
2015139
201659
2017209
2018129
201969
2020811.3
20212211.3
20221711.3
20231211.3
20241311.3
2025211.3
2026511.3
First to last qualifying date each year at Rocky Boy For each year, a bar from the first to the last day at Rocky Boy meeting 30 C (86 F). 1998: 17 July 1998 to 2 September 19981999: 28 July 1999 to 30 August 19992000: 13 July 2000 to 15 September 20002001: 28 July 2001 to 27 August 20012002: 27 June 2002 to 18 July 20022003: 30 June 2003 to 16 August 20032004: 17 July 2004 to 18 July 20042005: 8 July 2005 to 29 August 20052006: 28 June 2006 to 29 August 20062007: 6 July 2007 to 30 August 20072008: 30 June 2008 to 25 August 20082009: 23 July 2009 to 19 September 20092010: 29 June 2010 to 26 August 20102011: 3 July 2011 to 31 July 20112012: 25 June 2012 to 28 August 20122013: 2 July 2013 to 5 September 20132014: 30 July 2014 to 13 August 20142015: 27 June 2015 to 25 September 20152016: 8 June 2016 to 31 August 20162017: 26 June 2017 to 30 August 20172018: 6 July 2018 to 16 August 20182019: 23 July 2019 to 8 August 20192020: 22 July 2020 to 5 September 20202021: 3 June 2021 to 16 August 20212022: 15 July 2022 to 7 September 20222023: 21 July 2023 to 29 August 20232024: 10 July 2024 to 8 September 20242025: 8 July 2025 to 19 August 20252026: 11 July 2026 to 1 August 202619982002200620102014201820222026JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day at Rocky Boy meeting 30 C (86 F).
First to last qualifying date each year at Rocky Boy
YearFirst dateLast date
19981998-07-171998-09-02
19991999-07-281999-08-30
20002000-07-132000-09-15
20012001-07-282001-08-27
20022002-06-272002-07-18
20032003-06-302003-08-16
20042004-07-172004-07-18
20052005-07-082005-08-29
20062006-06-282006-08-29
20072007-07-062007-08-30
20082008-06-302008-08-25
20092009-07-232009-09-19
20102010-06-292010-08-26
20112011-07-032011-07-31
20122012-06-252012-08-28
20132013-07-022013-09-05
20142014-07-302014-08-13
20152015-06-272015-09-25
20162016-06-082016-08-31
20172017-06-262017-08-30
20182018-07-062018-08-16
20192019-07-232019-08-08
20202020-07-222020-09-05
20212021-06-032021-08-16
20222022-07-152022-09-07
20232023-07-212023-08-29
20242024-07-102024-09-08
20252025-07-082025-08-19
20262026-07-112026-08-01

Every Fixed Threshold

Fixed thresholds at Rocky Boy
ThresholdYears with a qualifying dayMost days in a yearYearLatest year days
30 C (86 F): Days292220215
35 C (95 F): Days2220181
90 F (32.2 C): Days20820214
0 C (32 F): Ice days (max3071201922
0 C (32 F): Frost days (min302282000122
-10 C (14 F): Days with min3090200027
-20 C (-4 F): Days with min3038201911
-30 C (-22 F): Days with min251220213
10 mm (0.39 in): Days with 10 mm or more rain3027202521
25 mm (0.98 in): Days with 25 mm or more rain301020166
50 mm (1.97 in): Days with 50 mm or more rain14420243
100 mm (3.94 in): Days with 100 mm or more rain1220242

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1998.

Download the Data

  • Data for Rocky Boy 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 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

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