Koster (Pol) Threshold Days by Year

4 fixed thresholds counted per year at Koster (Pol) (SF005107120): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Koster (Pol) Thresholds

Koster (Pol): days with 10 mm (0.39 in) or more of precipitation in 78 years, most in 1967 with 38.
Koster (Pol): days with 25 mm (0.98 in) or more of precipitation in 78 years, most in 1976 with 17.
Koster (Pol): days with 50 mm (1.97 in) or more of precipitation in 54 years, most in 1977 with 7.
Koster (Pol): days with 100 mm (3.94 in) or more of precipitation in 5 years, most in 1946 with 1.
4 fixed thresholds have at least one qualifying day at Koster (Pol).

Days with 10 mm (0.39 in) or more of precipitation

78 years with a qualifying day

Days per year at Koster (Pol) with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 38 in 1967.

Days with 10 mm (0.39 in) or more of precipitation per year at Koster (Pol)
Year	Days	Decade average
1912	11	14.8
1913	12	14.8
1914	19	14.8
1915	20	14.8
1916	12	14.8
1920	15	24.4
1924	31	24.4
1925	31	24.4
1926	17	24.4
1927	20	24.4
1928	22	24.4
1929	35	24.4
1930	13	22.1
1931	22	22.1
1932	17	22.1
1933	17	22.1
1934	29	22.1
1936	24	22.1
1937	22	22.1
1938	19	22.1
1939	36	22.1
1940	27	23
1941	17	23
1942	27	23
1943	32	23
1944	22	23
1945	10	23
1946	27	23
1947	19	23
1948	20	23
1949	29	23
1950	22	23.8
1951	19	23.8
1952	21	23.8
1953	17	23.8
1954	18	23.8
1955	34	23.8
1956	28	23.8
1957	34	23.8
1958	24	23.8
1959	21	23.8
1960	22	23.2
1961	24	23.2
1962	20	23.2
1963	23	23.2
1964	14	23.2
1965	17	23.2
1966	26	23.2
1967	38	23.2
1968	22	23.2
1969	26	23.2
1970	22	24.7
1971	25	24.7
1972	22	24.7
1973	24	24.7
1974	33	24.7
1975	22	24.7
1976	29	24.7
1977	24	24.7
1978	19	24.7
1979	27	24.7
1980	27	20
1981	24	20
1982	15	20
1983	16	20
1984	10	20
1985	19	20
1986	20	20
1987	21	20
1988	24	20
1989	24	20
1990	20	20.1
1991	22	20.1
1992	16	20.1
1993	19	20.1
1994	17	20.1
1995	26	20.1
1996	21	20.1

For each year, a bar from the first to the last day at Koster (Pol) meeting 10 mm (0.39 in).

First to last qualifying date each year at Koster (Pol)
Year	First date	Last date
1912	1912-01-04	1912-03-31
1913	1913-01-07	1913-10-12
1914	1914-02-05	1914-12-26
1915	1915-01-06	1915-12-07
1916	1916-01-05	1916-12-27
1920	1920-01-11	1920-11-27
1924	1924-01-07	1924-12-29
1925	1925-01-10	1925-11-27
1926	1926-01-10	1926-12-12
1927	1927-01-03	1927-12-22
1928	1928-01-05	1928-12-27
1929	1929-01-11	1929-12-24
1930	1930-02-13	1930-12-31
1931	1931-01-12	1931-12-21
1932	1932-01-06	1932-12-31
1933	1933-01-17	1933-12-31
1934	1934-01-03	1934-12-27
1936	1936-01-11	1936-12-15
1937	1937-01-06	1937-12-31
1938	1938-01-12	1938-12-30
1939	1939-01-03	1939-12-29
1940	1940-01-17	1940-12-24
1941	1941-02-12	1941-12-13
1942	1942-01-03	1942-12-16
1943	1943-01-01	1943-12-28
1944	1944-01-06	1944-12-28
1945	1945-01-19	1945-12-29
1946	1946-01-10	1946-12-23
1947	1947-01-04	1947-12-15
1948	1948-01-16	1948-11-09
1949	1949-01-19	1949-12-29
1950	1950-01-04	1950-12-31
1951	1951-01-18	1951-12-25
1952	1952-01-08	1952-12-31
1953	1953-01-05	1953-12-19
1954	1954-01-02	1954-12-27
1955	1955-01-02	1955-12-30
1956	1956-01-15	1956-12-28
1957	1957-01-11	1957-11-24
1958	1958-01-11	1958-12-28
1959	1959-01-07	1959-12-22
1960	1960-01-24	1960-12-20
1961	1961-01-28	1961-12-27
1962	1962-01-19	1962-12-17
1963	1963-01-07	1963-12-22
1964	1964-01-26	1964-12-29
1965	1965-01-14	1965-12-06
1966	1966-01-02	1966-12-20
1967	1967-01-03	1967-12-09
1968	1968-01-17	1968-12-21
1969	1969-01-02	1969-12-24
1970	1970-01-15	1970-12-27
1971	1971-01-06	1971-12-27
1972	1972-01-02	1972-12-31
1973	1973-01-06	1973-12-19
1974	1974-01-13	1974-12-27
1975	1975-01-15	1975-12-18
1976	1976-01-11	1976-11-04
1977	1977-01-10	1977-12-31
1978	1978-01-01	1978-12-27
1979	1979-01-12	1979-12-27
1980	1980-01-06	1980-12-26
1981	1981-01-19	1981-12-29
1982	1982-01-02	1982-12-07
1983	1983-01-02	1983-12-26
1984	1984-01-09	1984-12-18
1985	1985-01-06	1985-12-22
1986	1986-01-02	1986-12-29
1987	1987-01-11	1987-12-15
1988	1988-01-04	1988-12-26
1989	1989-01-03	1989-12-28
1990	1990-01-08	1990-12-15
1991	1991-01-02	1991-12-24
1992	1992-01-12	1992-12-22
1993	1993-09-30	1993-12-28
1994	1994-01-12	1994-12-25
1995	1995-01-06	1995-12-26
1996	1996-01-08	1996-12-16

Every Fixed Threshold

Fixed thresholds at Koster (Pol)
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
10 mm (0.39 in): Days with 10 mm or more rain	78	38	1967	21
25 mm (0.98 in): Days with 25 mm or more rain	78	17	1976	11
50 mm (1.97 in): Days with 50 mm or more rain	54	7	1977	3
100 mm (3.94 in): Days with 100 mm or more rain	5	1	1946	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1912.

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Data for Koster (Pol) 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).

Koster (Pol) Threshold Days by Year

Key Facts for Koster (Pol) Thresholds

Days with 10 mm (0.39 in) or more of precipitation

Every Fixed Threshold

Download the Data

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