Sandy Lake Dam Libby Threshold Days by Year (USC00217460)

18 fixed thresholds counted per year at Sandy Lake Dam Libby (USC00217460): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Sandy Lake Dam Libby Thresholds

Sandy Lake Dam Libby: nights with a minimum temperature at or below 0 C (32 F) in 104 years, most in 1917 with 230.
Sandy Lake Dam Libby: nights with a minimum temperature at or below -10 C (14 F) in 104 years, most in 1937 with 123.
Sandy Lake Dam Libby: nights with a minimum temperature at or below -20 C (-4 F) in 104 years, most in 1917 with 64.
Sandy Lake Dam Libby: nights with a minimum temperature at or below -30 C (-22 F) in 103 years, most in 1917 with 29.
18 fixed thresholds have at least one qualifying day at Sandy Lake Dam Libby.

Days at or above 30 C (86 F)

101 years with a qualifying day

Days per year at Sandy Lake Dam Libby with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 51 in 1988.

Days at or above 30 C (86 F) per year at Sandy Lake Dam Libby
Year	Days	Decade average
1898	10	7
1899	4	7
1900	18	9.5
1901	18	9.5
1902	3	9.5
1903	4	9.5
1904	3	9.5
1905	6	9.5
1906	16	9.5
1907	7	9.5
1908	14	9.5
1909	6	9.5
1911	8	12.2
1912	10	12.2
1913	12	12.2
1914	11	12.2
1915	7	12.2
1916	26	12.2
1917	9	12.2
1918	9	12.2
1919	18	12.2
1920	3	13.3
1921	30	13.3
1922	17	13.3
1923	17	13.3
1924	4	13.3
1925	20	13.3
1926	11	13.3
1927	6	13.3
1928	5	13.3
1929	20	13.3
1930	21	15.6
1931	26	15.6
1932	15	15.6
1933	19	15.6
1934	13	15.6
1935	8	15.6
1936	29	15.6
1937	14	15.6
1938	1	15.6
1939	10	15.6
1940	6	10.6
1941	14	10.6
1942	4	10.6
1943	12	10.6
1944	9	10.6
1945	8	10.6
1946	5	10.6
1947	19	10.6
1948	15	10.6
1949	14	10.6
1950	3	6.6
1951	1	6.6
1952	9	6.6
1953	7	6.6
1954	2	6.6
1955	13	6.6
1956	4	6.6
1957	6	6.6
1958	7	6.6
1959	14	6.6
1960	7	12.7
1961	30	12.7
1962	2	12.7
1963	14	12.7
1964	26	12.7
1965	6	12.7
1966	15	12.7
1967	6	12.7
1968	7	12.7
1969	14	12.7
1970	30	18.2
1971	9	18.2
1972	13	18.2
1973	10	18.2
1974	14	18.2
1975	23	18.2
1976	41	18.2
1977	13	18.2
1978	20	18.2
1979	9	18.2
1980	25	22
1981	7	22
1982	6	22
1983	34	22
1984	21	22
1985	4	22
1986	17	22
1987	31	22
1988	51	22
1989	24	22
2015	13	11.3
2018	15	11.3
2019	6	11.3
2020	14	13.4
2021	29	13.4
2022	8	13.4
2023	16	13.4
2024	2	13.4
2025	12	13.4
2026	13	13.4

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

First to last qualifying date each year at Sandy Lake Dam Libby
Year	First date	Last date
1898	1898-06-17	1898-09-02
1899	1899-07-18	1899-08-28
1900	1900-05-13	1900-08-31
1901	1901-05-01	1901-08-21
1902	1902-07-22	1902-07-24
1903	1903-06-05	1903-07-23
1904	1904-07-16	1904-08-15
1905	1905-07-15	1905-08-29
1906	1906-06-16	1906-09-10
1907	1907-06-16	1907-08-31
1908	1908-07-06	1908-09-22
1909	1909-06-20	1909-07-28
1911	1911-06-19	1911-07-30
1912	1912-06-24	1912-09-08
1913	1913-06-15	1913-09-06
1914	1914-05-25	1914-08-08
1915	1915-07-12	1915-09-06
1916	1916-07-01	1916-08-19
1917	1917-07-19	1917-08-22
1918	1918-05-05	1918-08-25
1919	1919-05-27	1919-08-05
1920	1920-06-13	1920-08-10
1921	1921-05-21	1921-09-02
1922	1922-06-06	1922-09-22
1923	1923-06-01	1923-08-13
1924	1924-07-11	1924-08-29
1925	1925-05-19	1925-09-03
1926	1926-05-05	1926-08-28
1927	1927-06-28	1927-09-14
1928	1928-08-07	1928-08-14
1929	1929-06-10	1929-09-04
1930	1930-07-04	1930-08-31
1931	1931-05-15	1931-09-11
1932	1932-05-14	1932-08-30
1933	1933-06-05	1933-08-15
1934	1934-05-09	1934-08-18
1935	1935-07-03	1935-08-11
1936	1936-05-16	1936-09-22
1937	1937-07-02	1937-09-01
1938	1938-08-01	1938-08-01
1939	1939-05-30	1939-09-15
1940	1940-07-20	1940-08-13
1941	1941-06-19	1941-08-07
1942	1942-07-12	1942-08-21
1943	1943-06-19	1943-08-23
1944	1944-06-25	1944-08-11
1945	1945-06-23	1945-08-19
1946	1946-07-05	1946-08-02
1947	1947-07-11	1947-09-09
1948	1948-06-02	1948-09-16
1949	1949-05-03	1949-08-26
1950	1950-06-22	1950-08-16
1951	1951-07-25	1951-07-25
1952	1952-04-27	1952-08-15
1953	1953-06-18	1953-09-02
1954	1954-07-13	1954-07-26
1955	1955-06-30	1955-08-19
1956	1956-06-09	1956-06-12
1957	1957-07-10	1957-08-01
1958	1958-07-23	1958-08-12
1959	1959-05-01	1959-08-25
1960	1960-07-21	1960-09-06
1961	1961-05-31	1961-09-09
1962	1962-06-28	1962-06-29
1963	1963-06-25	1963-10-05
1964	1964-05-18	1964-08-06
1965	1965-07-22	1965-08-14
1966	1966-06-22	1966-09-01
1967	1967-07-10	1967-07-24
1968	1968-06-04	1968-08-07
1969	1969-05-27	1969-08-30
1970	1970-05-19	1970-09-06
1971	1971-06-13	1971-09-03
1972	1972-05-17	1972-08-30
1973	1973-06-10	1973-08-30
1974	1974-07-01	1974-07-19
1975	1975-06-28	1975-08-25
1976	1976-06-03	1976-09-12
1977	1977-05-13	1977-07-20
1978	1978-05-26	1978-09-07
1979	1979-06-15	1979-09-05
1980	1980-04-21	1980-07-16
1981	1981-07-05	1981-08-14
1982	1982-07-05	1982-08-07
1983	1983-06-22	1983-09-03
1984	1984-07-03	1984-09-20
1985	1985-06-08	1985-07-08
1986	1986-05-28	1986-07-25
1987	1987-04-18	1987-08-16
1988	1988-05-26	1988-08-17
1989	1989-06-19	1989-08-12
2015	2015-06-10	2015-10-11
2018	2018-05-08	2018-09-17
2019	2019-06-08	2019-08-04
2020	2020-06-09	2020-07-27
2021	2021-05-02	2021-08-24
2022	2022-06-15	2022-08-06
2023	2023-06-02	2023-09-05
2024	2024-07-28	2024-08-27
2025	2025-05-12	2025-09-30
2026	2026-05-27	2026-10-11

Every Fixed Threshold

Fixed thresholds at Sandy Lake Dam Libby
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	101	51	1988	13
35 C (95 F): Days	21	10	1988	1
90 F (32.2 C): Days	79	23	1988	5
100 F (37.8 C): Days	4	2	1988	2
0 C (32 F): Ice days (max	101	124	1955	55
0 C (32 F): Frost days (min	104	230	1917	117
-10 C (14 F): Days with min	104	123	1937	57
-20 C (-4 F): Days with min	104	64	1917	24
-30 C (-22 F): Days with min	103	29	1917	4
-40 C (-40 F): Days with min	37	7	1899	1
20 C (68 F): Tropical nights (min	85	12	1921	7
25 C (77 F): Days with min	3	1	1917	1
10 mm (0.39 in): Days with 10 mm or more rain	95	34	1903	17
25 mm (0.98 in): Days with 25 mm or more rain	95	15	1953	5
50 mm (1.97 in): Days with 50 mm or more rain	50	4	1942	1
100 mm (3.94 in): Days with 100 mm or more rain	5	1	1953	1
10 cm (3.9 in): Days with 10 cm or more snowfall	64	11	1965	2
25 cm (9.8 in): Days with 25 cm or more snowfall	16	3	1965	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1898.

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Data for Sandy Lake Dam Libby 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 2026-10-17. Last revised 17 October 2026 (2026-10-17).

Sandy Lake Dam Libby Threshold Days by Year (USC00217460)

Key Facts for Sandy Lake Dam Libby Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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