Roy Threshold Days by Year (USC00297638)

18 fixed thresholds counted per year at Roy (USC00297638): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Roy Thresholds

Roy: days with 10 mm (0.39 in) or more of precipitation in 92 years, most in 1941 with 26.
Roy: days with 25 mm (0.98 in) or more of precipitation in 84 years, most in 1941 with 9.
Roy: nights with a minimum temperature at or below 0 C (32 F) in 65 years, most in 1976 with 174.
Roy: nights with a minimum temperature at or below -10 C (14 F) in 65 years, most in 1966 with 43.
18 fixed thresholds have at least one qualifying day at Roy.

Days at or above 30 C (86 F)

62 years with a qualifying day

Days per year at Roy with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 96 in 1934.

Days at or above 30 C (86 F) per year at Roy
Year	Days	Decade average
1914	29	58.3
1915	45	58.3
1916	84	58.3
1917	67	58.3
1918	61	58.3
1919	64	58.3
1920	29	36.9
1921	13	36.9
1923	27	36.9
1924	45	36.9
1925	53	36.9
1926	39	36.9
1927	52	36.9
1934	96	78.5
1935	61	78.5
1951	63	62.7
1952	64	62.7
1954	87	62.7
1955	53	62.7
1956	82	62.7
1957	60	62.7
1959	30	62.7
1961	32	42.8
1965	37	42.8
1966	54	42.8
1967	34	42.8
1968	47	42.8
1969	53	42.8
1970	59	50.8
1971	35	50.8
1972	29	50.8
1973	46	50.8
1974	65	50.8
1975	36	50.8
1976	47	50.8
1977	68	50.8
1978	73	50.8
1979	50	50.8
1980	78	47
1981	61	47
1983	66	47
1984	53	47
1985	50	47
1986	21	47
1987	27	47
1988	50	47
1989	17	47
1990	46	35.1
1991	19	35.1
1992	19	35.1
1993	42	35.1
1995	43	35.1
1996	34	35.1
1998	43	35.1
2002	71	56.2
2005	42	56.2
2006	49	56.2
2007	65	56.2
2008	49	56.2
2009	61	56.2
2010	75	83
2011	91	83

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

First to last qualifying date each year at Roy
Year	First date	Last date
1914	1914-06-11	1914-10-01
1915	1915-05-11	1915-09-10
1916	1916-05-05	1916-09-10
1917	1917-06-08	1917-09-07
1918	1918-05-08	1918-08-29
1919	1919-04-19	1919-09-13
1920	1920-06-25	1920-08-30
1921	1921-06-25	1921-08-16
1923	1923-06-30	1923-09-11
1924	1924-06-05	1924-09-22
1925	1925-05-19	1925-09-19
1926	1926-06-01	1926-09-15
1927	1927-05-01	1927-09-09
1934	1934-05-07	1934-08-29
1935	1935-06-15	1935-08-28
1951	1951-05-27	1951-09-26
1952	1952-05-05	1952-09-20
1954	1954-06-01	1954-10-04
1955	1955-06-16	1955-09-18
1956	1956-05-05	1956-10-06
1957	1957-06-06	1957-09-30
1959	1959-04-26	1959-09-15
1961	1961-05-11	1961-09-02
1965	1965-04-21	1965-10-09
1966	1966-05-07	1966-09-24
1967	1967-05-09	1967-10-03
1968	1968-05-22	1968-09-19
1969	1969-05-21	1969-09-07
1970	1970-06-13	1970-09-11
1971	1971-06-15	1971-09-13
1972	1972-06-01	1972-08-21
1973	1973-06-08	1973-09-21
1974	1974-05-10	1974-09-11
1975	1975-07-01	1975-09-02
1976	1976-06-09	1976-09-11
1977	1977-05-30	1977-09-30
1978	1978-05-14	1978-10-01
1979	1979-06-13	1979-10-08
1980	1980-06-03	1980-09-21
1981	1981-04-29	1981-09-20
1983	1983-06-18	1983-09-19
1984	1984-05-10	1984-09-12
1985	1985-06-07	1985-09-08
1986	1986-07-03	1986-08-21
1987	1987-06-16	1987-08-21
1988	1988-05-14	1988-08-26
1989	1989-05-20	1989-08-15
1990	1990-05-22	1990-09-01
1991	1991-06-18	1991-07-31
1992	1992-06-30	1992-09-17
1993	1993-06-12	1993-08-24
1995	1995-06-13	1995-09-06
1996	1996-05-08	1996-08-14
1998	1998-05-18	1998-09-27
2002	2002-05-28	2002-09-07
2005	2005-05-21	2005-09-25
2006	2006-05-19	2006-08-24
2007	2007-06-18	2007-09-19
2008	2008-05-19	2008-09-07
2009	2009-05-07	2009-09-27
2010	2010-05-28	2010-09-29
2011	2011-05-27	2011-09-24

Every Fixed Threshold

Fixed thresholds at Roy
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	62	96	1934	91
35 C (95 F): Days	41	56	1934	16
40 C (104 F): Days	1	1	1919	1
90 F (32.2 C): Days	61	84	1934	59
100 F (37.8 C): Days	14	6	1934	1
0 C (32 F): Ice days (max	60	37	1918	18
0 C (32 F): Frost days (min	65	174	1976	142
-10 C (14 F): Days with min	65	43	1966	34
-20 C (-4 F): Days with min	34	7	1918	5
20 C (68 F): Tropical nights (min	27	24	1934	2
25 C (77 F): Days with min	1	4	1980	4
10 mm (0.39 in): Days with 10 mm or more rain	92	26	1941	8
25 mm (0.98 in): Days with 25 mm or more rain	84	9	1941	3
50 mm (1.97 in): Days with 50 mm or more rain	29	4	1930	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1914	1
10 cm (3.9 in): Days with 10 cm or more snowfall	60	9	1918	3
25 cm (9.8 in): Days with 25 cm or more snowfall	14	2	1990	1
50 cm (19.7 in): Days with 50 cm or more snowfall	1	1	1940	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1914.

Download the Data

Data for Roy 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 2025-12-31. Last revised 31 December 2025 (2025-12-31).

Roy Threshold Days by Year (USC00297638)

Key Facts for Roy Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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