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Data as of 2025-12-31
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Built 2026-10-19 (19 October 2026)

Rocky Boy Threshold Days by Year (USC00247148)

7 fixed thresholds counted per year at Rocky Boy (USC00247148): 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 10 mm (0.39 in) or more of precipitation in 21 years, most in 1954 with 18.
  • Rocky Boy: days with 25 mm (0.98 in) or more of precipitation in 19 years, most in 1986 with 7.
  • Rocky Boy: days with 10 cm (3.9 in) or more of snowfall in 12 years, most in 1957 with 9.
  • Rocky Boy: days with 50 mm (1.97 in) or more of precipitation in 9 years, most in 1964 with 3.
  • 7 fixed thresholds have at least one qualifying day at Rocky Boy.
21 years with a qualifying day
Days with 10 mm (0.39 in) or more of precipitation per year at Rocky Boy Days per year at Rocky Boy with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 18 in 1954. 051015201952: 81953: 151954: 181956: 91957: 101958: 111959: 101960: 91961: 61962: 21963: 91964: 181965: 141966: 161967: 71970: 101971: 121976: 61980: 81981: 91986: 161952195619591962196519701980
Days per year at Rocky Boy with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 18 in 1954.
Days with 10 mm (0.39 in) or more of precipitation per year at Rocky Boy
YearDaysDecade average
1952811.6
19531511.6
19541811.6
1956911.6
19571011.6
19581111.6
19591011.6
1960910.1
1961610.1
1962210.1
1963910.1
19641810.1
19651410.1
19661610.1
1967710.1
1970109.3
1971129.3
197669.3
1980811
1981911
19861611
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 10 mm (0.39 in). 1952: 3 May 1952 to 20 July 19521953: 6 March 1953 to 20 December 19531954: 10 March 1954 to 24 October 19541956: 8 May 1956 to 18 November 19561957: 21 May 1957 to 19 October 19571958: 26 February 1958 to 4 November 19581959: 14 April 1959 to 23 November 19591960: 12 April 1960 to 29 October 19601961: 7 May 1961 to 11 September 19611962: 13 June 1962 to 13 July 19621963: 19 January 1963 to 2 September 19631964: 2 April 1964 to 25 September 19641965: 21 January 1965 to 15 September 19651966: 26 April 1966 to 2 October 19661967: 29 March 1967 to 13 September 19671970: 29 April 1970 to 17 December 19701971: 9 January 1971 to 2 September 19711976: 7 June 1976 to 25 November 19761980: 10 April 1980 to 27 October 19801981: 30 March 1981 to 25 September 19811986: 5 May 1986 to 31 October 19861952195619591962196519701980JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day at Rocky Boy meeting 10 mm (0.39 in).
First to last qualifying date each year at Rocky Boy
YearFirst dateLast date
19521952-05-031952-07-20
19531953-03-061953-12-20
19541954-03-101954-10-24
19561956-05-081956-11-18
19571957-05-211957-10-19
19581958-02-261958-11-04
19591959-04-141959-11-23
19601960-04-121960-10-29
19611961-05-071961-09-11
19621962-06-131962-07-13
19631963-01-191963-09-02
19641964-04-021964-09-25
19651965-01-211965-09-15
19661966-04-261966-10-02
19671967-03-291967-09-13
19701970-04-291970-12-17
19711971-01-091971-09-02
19761976-06-071976-11-25
19801980-04-101980-10-27
19811981-03-301981-09-25
19861986-05-051986-10-31

Every Fixed Threshold

Fixed thresholds at Rocky Boy
ThresholdYears with a qualifying dayMost days in a yearYearLatest year days
10 mm (0.39 in): Days with 10 mm or more rain2118195416
25 mm (0.98 in): Days with 25 mm or more rain19719867
50 mm (1.97 in): Days with 50 mm or more rain9319642
100 mm (3.94 in): Days with 100 mm or more rain2119591
10 cm (3.9 in): Days with 10 cm or more snowfall12919573
25 cm (9.8 in): Days with 25 cm or more snowfall2319822
50 cm (19.7 in): Days with 50 cm or more snowfall2219821

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1952.

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 (2025-12-31).