Shamrock Threshold Days by Year (USC00418235)

6 fixed thresholds counted per year at Shamrock (USC00418235): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Shamrock Thresholds

Shamrock: days with 10 mm (0.39 in) or more of precipitation in 57 years, most in 1941 with 29.
Shamrock: days with 25 mm (0.98 in) or more of precipitation in 56 years, most in 1959 with 13.
Shamrock: days with 50 mm (1.97 in) or more of precipitation in 40 years, most in 1934 with 5.
Shamrock: days with 10 cm (3.9 in) or more of snowfall in 26 years, most in 1931 with 4.
6 fixed thresholds have at least one qualifying day at Shamrock.

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

57 years with a qualifying day

Days per year at Shamrock with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 29 in 1941.

Days with 10 mm (0.39 in) or more of precipitation per year at Shamrock
Year	Days	Decade average
1930	15	16
1931	18	16
1932	16	16
1933	15	16
1934	14	16
1935	19	16
1936	14	16
1937	14	16
1938	17	16
1939	18	16
1940	17	21.1
1941	29	21.1
1942	24	21.1
1943	15	21.1
1944	24	21.1
1945	14	21.1
1946	25	21.1
1947	20	21.1
1948	19	21.1
1949	24	21.1
1950	20	16.8
1951	17	16.8
1952	12	16.8
1953	13	16.8
1954	12	16.8
1955	20	16.8
1956	6	16.8
1957	22	16.8
1958	22	16.8
1959	24	16.8
1960	23	18.3
1961	20	18.3
1962	19	18.3
1963	15	18.3
1964	17	18.3
1965	18	18.3
1966	10	18.3
1967	19	18.3
1968	22	18.3
1969	20	18.3
1970	8	18.6
1971	17	18.6
1972	20	18.6
1973	27	18.6
1974	22	18.6
1975	20	18.6
1976	12	18.6
1977	22	18.6
1978	19	18.6
1979	19	18.6
1980	12	18.6
1981	22	18.6
1982	23	18.6
1983	14	18.6
1984	13	18.6
1985	23	18.6
1986	23	18.6

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

First to last qualifying date each year at Shamrock
Year	First date	Last date
1930	1930-01-08	1930-12-04
1931	1931-02-07	1931-12-20
1932	1932-02-20	1932-12-23
1933	1933-02-27	1933-11-03
1934	1934-03-01	1934-09-23
1935	1935-02-12	1935-12-28
1936	1936-04-20	1936-10-08
1937	1937-04-20	1937-10-13
1938	1938-02-17	1938-11-03
1939	1939-01-08	1939-12-26
1940	1940-02-03	1940-11-25
1941	1941-02-01	1941-12-12
1942	1942-02-15	1942-12-21
1943	1943-05-09	1943-12-09
1944	1944-01-01	1944-12-04
1945	1945-01-20	1945-09-29
1946	1946-01-14	1946-12-11
1947	1947-03-12	1947-12-05
1948	1948-02-25	1948-11-01
1949	1949-01-10	1949-12-21
1950	1950-02-12	1950-09-26
1951	1951-01-14	1951-11-25
1952	1952-04-09	1952-12-19
1953	1953-03-01	1953-10-25
1954	1954-04-26	1954-10-07
1955	1955-02-04	1955-10-04
1956	1956-05-01	1956-10-15
1957	1957-02-18	1957-11-04
1958	1958-01-19	1958-09-23
1959	1959-03-26	1959-12-25
1960	1960-01-14	1960-12-10
1961	1961-02-05	1961-11-15
1962	1962-01-05	1962-12-02
1963	1963-02-11	1963-09-16
1964	1964-02-04	1964-12-10
1965	1965-03-12	1965-10-18
1966	1966-04-23	1966-09-28
1967	1967-03-20	1967-10-07
1968	1968-01-22	1968-11-15
1969	1969-02-14	1969-12-06
1970	1970-04-01	1970-09-15
1971	1971-02-19	1971-12-03
1972	1972-04-30	1972-11-18
1973	1973-01-07	1973-10-11
1974	1974-01-10	1974-10-31
1975	1975-01-02	1975-12-29
1976	1976-04-08	1976-09-16
1977	1977-02-12	1977-11-09
1978	1978-02-09	1978-11-15
1979	1979-01-19	1979-11-21
1980	1980-02-08	1980-12-08
1981	1981-03-04	1981-11-01
1982	1982-03-14	1982-12-27
1983	1983-02-01	1983-10-21
1984	1984-01-18	1984-12-16
1985	1985-01-27	1985-11-15
1986	1986-05-09	1986-11-04

Every Fixed Threshold

Fixed thresholds at Shamrock
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	57	29	1941	23
25 mm (0.98 in): Days with 25 mm or more rain	56	13	1959	10
50 mm (1.97 in): Days with 50 mm or more rain	40	5	1934	3
100 mm (3.94 in): Days with 100 mm or more rain	5	1	1934	1
10 cm (3.9 in): Days with 10 cm or more snowfall	26	4	1931	1
25 cm (9.8 in): Days with 25 cm or more snowfall	1	1	1964	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1930.

Download the Data

Data for Shamrock 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).

Shamrock Threshold Days by Year (USC00418235)

Key Facts for Shamrock Thresholds

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

Every Fixed Threshold

Download the Data

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