Bollier Threshold Days by Year

5 fixed thresholds counted per year at Bollier (ASN00040577): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Bollier Thresholds

Bollier: days with 10 mm (0.39 in) or more of precipitation in 43 years, most in 1921 with 55.
Bollier: days with 25 mm (0.98 in) or more of precipitation in 43 years, most in 1921 with 21.
Bollier: days with 50 mm (1.97 in) or more of precipitation in 41 years, most in 1963 with 11.
Bollier: days with 100 mm (3.94 in) or more of precipitation in 24 years, most in 1947 with 3.
5 fixed thresholds have at least one qualifying day at Bollier.

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

43 years with a qualifying day

Days per year at Bollier with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 55 in 1921.

Days with 10 mm (0.39 in) or more of precipitation per year at Bollier
Year	Days	Decade average
1921	55	39.2
1922	34	39.2
1923	35	39.2
1924	40	39.2
1925	43	39.2
1926	25	39.2
1927	48	39.2
1928	38	39.2
1929	35	39.2
1930	45	34
1931	31	34
1932	24	34
1933	40	34
1934	40	34
1935	41	34
1936	24	34
1937	30	34
1938	37	34
1939	28	34
1940	25	30.6
1941	26	30.6
1942	25	30.6
1943	38	30.6
1944	23	30.6
1945	33	30.6
1946	35	30.6
1947	40	30.6
1948	26	30.6
1949	35	30.6
1950	49	32.8
1951	15	32.8
1952	32	32.8
1953	35	32.8
1954	32	32.8
1955	35	32.8
1956	42	32.8
1957	17	32.8
1958	34	32.8
1959	37	32.8
1962	36	35.3
1963	35	35.3
1964	36	35.3
1966	34	35.3

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

First to last qualifying date each year at Bollier
Year	First date	Last date
1921	1921-01-07	1921-12-31
1922	1922-01-15	1922-12-27
1923	1923-01-07	1923-12-27
1924	1924-01-07	1924-12-31
1925	1925-01-02	1925-12-30
1926	1926-01-04	1926-12-21
1927	1927-01-10	1927-12-26
1928	1928-01-08	1928-12-31
1929	1929-01-12	1929-12-31
1930	1930-01-01	1930-12-18
1931	1931-01-20	1931-12-23
1932	1932-01-11	1932-12-22
1933	1933-01-19	1933-12-29
1934	1934-01-02	1934-12-25
1935	1935-01-06	1935-12-28
1936	1936-01-10	1936-12-16
1937	1937-01-03	1937-12-19
1938	1938-01-04	1938-11-07
1939	1939-01-18	1939-12-27
1940	1940-01-12	1940-12-22
1941	1941-01-07	1941-12-29
1942	1942-01-17	1942-12-30
1943	1943-01-03	1943-12-30
1944	1944-01-08	1944-12-19
1945	1945-01-02	1945-12-20
1946	1946-01-14	1946-12-30
1947	1947-01-11	1947-12-21
1948	1948-01-02	1948-12-21
1949	1949-01-09	1949-12-17
1950	1950-01-14	1950-12-20
1951	1951-01-25	1951-12-19
1952	1952-01-09	1952-12-31
1953	1953-01-08	1953-12-28
1954	1954-01-03	1954-12-17
1955	1955-01-22	1955-12-31
1956	1956-01-03	1956-12-23
1957	1957-01-08	1957-12-16
1958	1958-01-13	1958-12-31
1959	1959-01-04	1959-12-27
1962	1962-01-05	1962-12-31
1963	1963-01-01	1963-12-31
1964	1964-01-03	1964-12-07
1966	1966-01-23	1966-12-31

Every Fixed Threshold

Fixed thresholds at Bollier
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	43	55	1921	34
25 mm (0.98 in): Days with 25 mm or more rain	43	21	1921	13
50 mm (1.97 in): Days with 50 mm or more rain	41	11	1963	2
100 mm (3.94 in): Days with 100 mm or more rain	24	3	1947	1
200 mm (7.87 in): Days with 200 mm or more rain	1	1	1955	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1921.

Download the Data

Data for Bollier 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 2026-10-16 (16 October 2026). Threshold counts are computed by this site.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).

Bollier Threshold Days by Year

Key Facts for Bollier Thresholds

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

Every Fixed Threshold

Download the Data

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