Castle Rock Threshold Days by Year (USC00051401)

17 fixed thresholds counted per year at Castle Rock (USC00051401): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Castle Rock Thresholds

Castle Rock: days with 10 mm (0.39 in) or more of precipitation in 75 years, most in 1987 with 24.
Castle Rock: days with a maximum temperature at or above 30 C (86 F) in 73 years, most in 2020 with 103.
Castle Rock: days with a maximum temperature at or above 90 F (32.2 C) in 73 years, most in 2020 with 73.
Castle Rock: days with a maximum temperature at or below 0 C (32 F) in 73 years, most in 1987 with 32.
17 fixed thresholds have at least one qualifying day at Castle Rock.

Days at or above 30 C (86 F)

73 years with a qualifying day

Days per year at Castle Rock with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 103 in 2020.

Days at or above 30 C (86 F) per year at Castle Rock
Year	Days	Decade average
1893	56	48.4
1894	54	48.4
1896	32	48.4
1897	54	48.4
1899	46	48.4
1900	39	40.3
1901	54	40.3
1902	55	40.3
1903	48	40.3
1906	46	40.3
1907	23	40.3
1908	17	40.3
1911	43	27.4
1912	20	27.4
1913	39	27.4
1914	26	27.4
1915	11	27.4
1916	32	27.4
1917	21	27.4
1921	26	40.2
1922	54	40.2
1923	19	40.2
1924	76	40.2
1927	29	40.2
1928	37	40.2
1963	49	41.4
1964	64	41.4
1965	20	41.4
1966	46	41.4
1967	22	41.4
1968	43	41.4
1969	46	41.4
1970	47	43.1
1971	50	43.1
1972	27	43.1
1973	35	43.1
1974	44	43.1
1975	43	43.1
1976	43	43.1
1977	46	43.1
1979	53	43.1
1981	59	35.8
1982	40	35.8
1986	25	35.8
1987	25	35.8
1988	37	35.8
1989	29	35.8
1990	28	39.3
1993	30	39.3
1994	57	39.3
1995	47	39.3
1996	49	39.3
1997	37	39.3
1998	37	39.3
1999	29	39.3
2000	57	46.5
2002	63	46.5
2003	48	46.5
2004	24	46.5
2005	40	46.5
2006	43	46.5
2007	48	46.5
2008	49	46.5
2010	49	56
2011	50	56
2012	65	56
2016	52	56
2017	51	56
2019	69	56
2020	103	72.5
2021	88	72.5
2023	41	72.5
2024	58	72.5

For each year, a bar from the first to the last day at Castle Rock meeting 30 C (86 F).

First to last qualifying date each year at Castle Rock
Year	First date	Last date
1893	1893-06-07	1893-09-14
1894	1894-05-19	1894-09-25
1896	1896-06-12	1896-09-06
1897	1897-06-08	1897-09-30
1899	1899-06-03	1899-09-30
1900	1900-05-31	1900-09-08
1901	1901-06-23	1901-08-28
1902	1902-06-05	1902-09-28
1903	1903-06-28	1903-09-10
1906	1906-06-09	1906-09-10
1907	1907-06-22	1907-09-12
1908	1908-06-11	1908-09-07
1911	1911-05-18	1911-09-26
1912	1912-05-30	1912-08-29
1913	1913-05-31	1913-08-27
1914	1914-06-10	1914-09-20
1915	1915-07-09	1915-10-09
1916	1916-05-09	1916-09-08
1917	1917-06-22	1917-09-06
1921	1921-06-25	1921-09-28
1922	1922-06-07	1922-10-05
1923	1923-06-23	1923-08-30
1924	1924-06-11	1924-09-16
1927	1927-04-26	1927-09-10
1928	1928-05-01	1928-09-30
1963	1963-06-06	1963-09-19
1964	1964-05-16	1964-09-09
1965	1965-06-28	1965-09-08
1966	1966-05-30	1966-08-30
1967	1967-05-24	1967-10-03
1968	1968-06-03	1968-08-27
1969	1969-05-25	1969-09-05
1970	1970-05-17	1970-09-11
1971	1971-06-05	1971-09-14
1972	1972-06-23	1972-08-19
1973	1973-06-10	1973-09-21
1974	1974-05-28	1974-09-11
1975	1975-06-25	1975-10-07
1976	1976-06-04	1976-08-30
1977	1977-06-03	1977-09-20
1979	1979-06-05	1979-09-10
1981	1981-04-27	1981-09-29
1982	1982-06-28	1982-09-10
1986	1986-06-15	1986-08-22
1987	1987-06-27	1987-08-21
1988	1988-06-07	1988-09-09
1989	1989-05-23	1989-09-06
1990	1990-06-04	1990-09-15
1993	1993-06-13	1993-09-13
1994	1994-06-05	1994-10-01
1995	1995-06-14	1995-09-18
1996	1996-05-15	1996-09-10
1997	1997-06-02	1997-08-30
1998	1998-06-02	1998-09-26
1999	1999-06-25	1999-09-26
2000	2000-05-06	2000-09-18
2002	2002-05-31	2002-09-08
2003	2003-05-30	2003-09-03
2004	2004-06-06	2004-09-19
2005	2005-05-21	2005-09-09
2006	2006-05-28	2006-08-25
2007	2007-06-12	2007-09-04
2008	2008-06-03	2008-09-01
2010	2010-05-28	2010-09-29
2011	2011-06-03	2011-09-02
2012	2012-05-05	2012-09-11
2016	2016-06-11	2016-09-21
2017	2017-06-16	2017-09-20
2019	2019-06-08	2019-09-30
2020	2020-05-01	2020-10-22
2021	2021-05-02	2021-10-26
2023	2023-06-20	2023-09-10
2024	2024-06-06	2024-10-05

Every Fixed Threshold

Fixed thresholds at Castle Rock
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	73	103	2020	58
35 C (95 F): Days	56	34	2021	3
90 F (32.2 C): Days	73	73	2020	25
100 F (37.8 C): Days	2	3	2012	3
0 C (32 F): Ice days (max	73	32	1987	13
0 C (32 F): Frost days (min	73	225	1912	153
-10 C (14 F): Days with min	73	85	1913	24
-20 C (-4 F): Days with min	69	29	1913	4
-30 C (-22 F): Days with min	19	5	1899	2
20 C (68 F): Tropical nights (min	6	9	2021	9
10 mm (0.39 in): Days with 10 mm or more rain	75	24	1987	17
25 mm (0.98 in): Days with 25 mm or more rain	69	7	1897	5
50 mm (1.97 in): Days with 50 mm or more rain	26	3	1897	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1897	1
10 cm (3.9 in): Days with 10 cm or more snowfall	50	14	1973	7
25 cm (9.8 in): Days with 25 cm or more snowfall	22	3	1966	1
50 cm (19.7 in): Days with 50 cm or more snowfall	4	1	1967	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1893.

Download the Data

Data for Castle Rock 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 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Castle Rock Threshold Days by Year (USC00051401)

Key Facts for Castle Rock Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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