Chelsea Threshold Days by Year (ASN00009006)

4 fixed thresholds counted per year at Chelsea (ASN00009006): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Chelsea Thresholds

Chelsea: days with 10 mm (0.39 in) or more of precipitation in 72 years, most in 1945 with 27.
Chelsea: days with 25 mm (0.98 in) or more of precipitation in 63 years, most in 1999 with 9.
Chelsea: days with 50 mm (1.97 in) or more of precipitation in 15 years, most in 1934 with 3.
Chelsea: days with 100 mm (3.94 in) or more of precipitation in 1 years, most in 1993 with 1.
4 fixed thresholds have at least one qualifying day at Chelsea.

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

72 years with a qualifying day

Days per year at Chelsea with 10 mm (0.39 in) or more of precipitation, with the decade average as a line. The most was 27 in 1945.

Days with 10 mm (0.39 in) or more of precipitation per year at Chelsea
Year	Days	Decade average
1931	20	15.9
1932	21	15.9
1933	17	15.9
1934	14	15.9
1935	15	15.9
1936	7	15.9
1937	12	15.9
1938	14	15.9
1939	23	15.9
1940	11	17.3
1941	16	17.3
1942	14	17.3
1943	16	17.3
1944	11	17.3
1945	27	17.3
1946	26	17.3
1963	26	17.4
1964	21	17.4
1965	18	17.4
1966	13	17.4
1967	13	17.4
1968	19	17.4
1969	12	17.4
1970	14	14.9
1971	14	14.9
1972	14	14.9
1973	19	14.9
1974	23	14.9
1975	18	14.9
1976	9	14.9
1977	10	14.9
1978	17	14.9
1979	11	14.9
1980	14	15.2
1981	16	15.2
1982	16	15.2
1983	18	15.2
1984	13	15.2
1985	12	15.2
1986	21	15.2
1987	16	15.2
1988	15	15.2
1989	11	15.2
1990	8	14.5
1991	15	14.5
1992	12	14.5
1993	11	14.5
1994	11	14.5
1995	23	14.5
1996	19	14.5
1997	11	14.5
1998	13	14.5
1999	22	14.5
2000	16	13.7
2001	8	13.7
2002	14	13.7
2003	16	13.7
2004	13	13.7
2005	19	13.7
2006	10	13.7
2015	11	13.8
2016	15	13.8
2017	12	13.8
2018	20	13.8
2019	11	13.8
2020	12	13.9
2021	24	13.9
2022	20	13.9
2023	5	13.9
2024	10	13.9
2025	14	13.9
2026	12	13.9

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

First to last qualifying date each year at Chelsea
Year	First date	Last date
1931	1931-05-04	1931-09-05
1932	1932-03-28	1932-10-29
1933	1933-02-03	1933-10-03
1934	1934-03-08	1934-07-29
1935	1935-01-06	1935-09-10
1936	1936-05-22	1936-09-30
1937	1937-04-19	1937-09-17
1938	1938-03-15	1938-11-02
1939	1939-01-20	1939-10-04
1940	1940-05-14	1940-12-03
1941	1941-04-27	1941-10-24
1942	1942-03-18	1942-10-27
1943	1943-01-31	1943-09-19
1944	1944-05-18	1944-12-04
1945	1945-03-26	1945-11-12
1946	1946-04-20	1946-11-13
1963	1963-02-20	1963-10-31
1964	1964-02-24	1964-10-09
1965	1965-05-04	1965-12-26
1966	1966-04-04	1966-10-09
1967	1967-04-22	1967-08-15
1968	1968-01-27	1968-10-05
1969	1969-04-08	1969-12-05
1970	1970-02-16	1970-10-04
1971	1971-03-12	1971-10-08
1972	1972-02-03	1972-10-08
1973	1973-05-13	1973-11-05
1974	1974-03-31	1974-10-19
1975	1975-03-21	1975-11-17
1976	1976-04-12	1976-11-11
1977	1977-05-10	1977-12-26
1978	1978-02-17	1978-12-16
1979	1979-03-15	1979-08-18
1980	1980-04-20	1980-10-22
1981	1981-02-17	1981-11-13
1982	1982-01-20	1982-09-16
1983	1983-05-03	1983-12-04
1984	1984-03-04	1984-11-16
1985	1985-02-09	1985-09-22
1986	1986-02-20	1986-10-05
1987	1987-04-26	1987-11-30
1988	1988-03-24	1988-12-03
1989	1989-02-25	1989-10-02
1990	1990-03-12	1990-10-06
1991	1991-01-18	1991-12-24
1992	1992-02-07	1992-11-20
1993	1993-05-02	1993-12-27
1994	1994-05-23	1994-09-11
1995	1995-02-24	1995-12-25
1996	1996-02-08	1996-11-07
1997	1997-04-04	1997-11-12
1998	1998-04-16	1998-08-29
1999	1999-03-19	1999-10-14
2000	2000-01-07	2000-09-06
2001	2001-05-06	2001-10-22
2002	2002-02-01	2002-12-23
2003	2003-03-30	2003-09-30
2004	2004-01-06	2004-09-06
2005	2005-03-02	2005-09-06
2006	2006-01-25	2006-11-04
2015	2015-02-02	2015-08-30
2016	2016-03-21	2016-08-27
2017	2017-01-28	2017-11-09
2018	2018-01-15	2018-10-14
2019	2019-06-07	2019-09-01
2020	2020-02-22	2020-11-14
2021	2021-02-06	2021-11-13
2022	2022-02-15	2022-11-18
2023	2023-03-31	2023-09-14
2024	2024-05-29	2024-10-02
2025	2025-06-05	2025-10-05
2026	2026-03-27	2026-07-18

Every Fixed Threshold

Fixed thresholds at Chelsea
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	72	27	1945	12
25 mm (0.98 in): Days with 25 mm or more rain	63	9	1999	4
50 mm (1.97 in): Days with 50 mm or more rain	15	3	1934	1
100 mm (3.94 in): Days with 100 mm or more rain	1	1	1993	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1931.

Download the Data

Data for Chelsea 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 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Chelsea Threshold Days by Year (ASN00009006)

Key Facts for Chelsea Thresholds

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

Every Fixed Threshold

Download the Data

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