Boston Threshold Days: Hot, Cold and Wet Days per Year

17 fixed thresholds counted per year for Boston: days at or above 30 C and 100 F, frost, tropical nights and heavy rain, with rankings and streaks.

Key Facts for Boston Thresholds

Boston: days with a maximum temperature at or above 30 C (86 F) in 91 years, most in 1983 with 52.
Boston: days with a maximum temperature at or above 90 F (32.2 C) in 91 years, most in 1983 with 30.
Boston: days with a maximum temperature at or below Ice days (max at or below 0 C) (32 F) in 91 years, most in 1989 with 44.
Boston: nights with a minimum temperature at or below Frost days (min at or below 0 C) (32 F) in 91 years, most in 1940 with 120.
17 fixed thresholds have at least one qualifying day at Boston.

Days at or above 30 C (86 F)

91 years with a qualifying day

Days per year in Boston with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 52 in 1983.

Days at or above 30 C (86 F) per year in Boston
Year	Days	Decade average
1936	16	23.5
1937	28	23.5
1938	25	23.5
1939	25	23.5
1940	11	28.7
1941	30	28.7
1942	26	28.7
1943	29	28.7
1944	37	28.7
1945	30	28.7
1946	24	28.7
1947	36	28.7
1948	28	28.7
1949	36	28.7
1950	22	30.2
1951	22	30.2
1952	40	30.2
1953	31	30.2
1954	19	30.2
1955	46	30.2
1956	32	30.2
1957	28	30.2
1958	22	30.2
1959	40	30.2
1960	25	24.8
1961	38	24.8
1962	17	24.8
1963	29	24.8
1964	16	24.8
1965	32	24.8
1966	33	24.8
1967	9	24.8
1968	22	24.8
1969	27	24.8
1970	31	30.5
1971	38	30.5
1972	21	30.5
1973	34	30.5
1974	20	30.5
1975	31	30.5
1976	37	30.5
1977	41	30.5
1978	25	30.5
1979	27	30.5
1980	37	27.3
1981	25	27.3
1982	15	27.3
1983	52	27.3
1984	34	27.3
1985	17	27.3
1986	21	27.3
1987	16	27.3
1988	37	27.3
1989	19	27.3
1990	28	29.7
1991	42	29.7
1992	15	29.7
1993	32	29.7
1994	44	29.7
1995	40	29.7
1996	15	29.7
1997	27	29.7
1998	24	29.7
1999	30	29.7
2000	15	25
2001	28	25
2002	40	25
2003	23	25
2004	15	25
2005	34	25
2006	23	25
2007	34	25
2008	19	25
2009	19	25
2010	45	32.6
2011	33	32.6
2012	28	32.6
2013	27	32.6
2014	18	32.6
2015	34	32.6
2016	39	32.6
2017	24	32.6
2018	40	32.6
2019	38	32.6
2020	35	32.7
2021	37	32.7
2022	38	32.7
2023	22	32.7
2024	31	32.7
2025	29	32.7
2026	37	32.7

For each year, a bar from the first to the last day in Boston meeting 30 C (86 F).

First to last qualifying date each year in Boston
Year	First date	Last date
1936	1936-05-18	1936-09-08
1937	1937-05-31	1937-09-04
1938	1938-04-28	1938-10-17
1939	1939-05-28	1939-10-10
1940	1940-06-03	1940-09-21
1941	1941-04-20	1941-09-23
1942	1942-04-30	1942-09-16
1943	1943-06-02	1943-08-24
1944	1944-05-27	1944-10-07
1945	1945-03-29	1945-09-29
1946	1946-05-25	1946-10-07
1947	1947-05-13	1947-10-17
1948	1948-06-24	1948-09-18
1949	1949-05-05	1949-10-10
1950	1950-06-08	1950-09-01
1951	1951-05-15	1951-09-13
1952	1952-06-09	1952-09-29
1953	1953-05-11	1953-09-07
1954	1954-06-01	1954-10-13
1955	1955-05-04	1955-09-19
1956	1956-05-31	1956-10-16
1957	1957-04-21	1957-09-16
1958	1958-06-30	1958-09-26
1959	1959-05-20	1959-09-24
1960	1960-06-16	1960-09-09
1961	1961-05-15	1961-09-26
1962	1962-04-27	1962-09-14
1963	1963-05-09	1963-10-07
1964	1964-05-08	1964-09-11
1965	1965-05-10	1965-09-23
1966	1966-05-27	1966-09-02
1967	1967-06-10	1967-08-18
1968	1968-06-06	1968-08-25
1969	1969-05-17	1969-09-01
1970	1970-05-10	1970-09-25
1971	1971-06-07	1971-10-02
1972	1972-05-29	1972-09-17
1973	1973-05-29	1973-09-04
1974	1974-05-17	1974-09-13
1975	1975-05-20	1975-08-27
1976	1976-04-18	1976-09-14
1977	1977-04-13	1977-09-02
1978	1978-05-29	1978-09-21
1979	1979-05-09	1979-08-30
1980	1980-05-22	1980-09-22
1981	1981-05-25	1981-09-14
1982	1982-07-07	1982-09-10
1983	1983-06-11	1983-09-20
1984	1984-05-26	1984-08-30
1985	1985-05-11	1985-09-21
1986	1986-05-19	1986-09-30
1987	1987-05-30	1987-09-09
1988	1988-06-12	1988-08-28
1989	1989-06-22	1989-09-10
1990	1990-04-27	1990-10-06
1991	1991-04-07	1991-09-17
1992	1992-05-22	1992-08-27
1993	1993-05-11	1993-09-15
1994	1994-04-27	1994-09-17
1995	1995-05-24	1995-09-14
1996	1996-05-20	1996-08-23
1997	1997-06-10	1997-08-17
1998	1998-03-31	1998-09-27
1999	1999-05-31	1999-09-03
2000	2000-05-07	2000-09-01
2001	2001-05-02	2001-09-13
2002	2002-04-17	2002-09-10
2003	2003-06-25	2003-08-27
2004	2004-04-19	2004-08-30
2005	2005-04-20	2005-09-14
2006	2006-06-01	2006-08-14
2007	2007-04-23	2007-10-04
2008	2008-06-03	2008-09-05
2009	2009-04-26	2009-08-26
2010	2010-04-07	2010-09-25
2011	2011-05-27	2011-10-09
2012	2012-04-16	2012-08-31
2013	2013-05-30	2013-09-12
2014	2014-06-18	2014-09-28
2015	2015-05-10	2015-09-17
2016	2016-05-25	2016-09-14
2017	2017-04-16	2017-09-27
2018	2018-05-02	2018-10-10
2019	2019-05-20	2019-09-23
2020	2020-06-04	2020-08-25
2021	2021-05-22	2021-09-15
2022	2022-05-14	2022-08-31
2023	2023-04-13	2023-09-08
2024	2024-05-22	2024-08-28
2025	2025-06-05	2025-09-06
2026	2026-05-17	2026-10-02

Every Fixed Threshold

Fixed thresholds in Boston
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days	Page
30 C (86 F): Days	91	52	1983	37	Full page
35 C (95 F): Days	69	14	1949	3	Full page
90 F (32.2 C): Days	91	30	1983	16	Full page
100 F (37.8 C): Days	16	2	1944	2	Full page
Ice days (max at or below 0 C) (32 F): Ice days (max	91	44	1989	22	Full page
Frost days (min at or below 0 C) (32 F): Frost days (min	91	120	1940	70	Full page
-10 C (14 F): Days with min	91	33	1948	15	Full page
-20 C (-4 F): Days with min	17	3	1942	2	Full page
Tropical nights (min at or above 20 C) (68 F): Tropical nights (min	91	49	1983	33	Full page
25 C (77 F): Days with min	31	4	2002	2	Full page
Days with 10 mm or more rain (0.39 in): Days with 10 mm or more rain	91	55	1958	15	Full page
Days with 25 mm or more rain (0.98 in): Days with 25 mm or more rain	91	20	1953	7	Full page
Days with 50 mm or more rain (1.97 in): Days with 50 mm or more rain	74	5	1954	1	Full page
Days with 100 mm or more rain (3.94 in): Days with 100 mm or more rain	9	2	1954	1	Full page
Days with 10 cm or more snowfall (3.9 in): Days with 10 cm or more snowfall	84	9	2005	4	Full page
Days with 25 cm or more snowfall (9.8 in): Days with 25 cm or more snowfall	40	4	2015	2	Full page
Days with 50 cm or more snowfall (19.7 in): Days with 50 cm or more snowfall	5	1	1978	1	Full page

A full page with streaks and every date exists for thresholds with at least 5 qualifying years. Years with under 90 percent of days observed are left out of the most days column.

Download the Data

Data for Boston 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 2026-10-12 (12 October 2026). Threshold counts are computed by this site from the threaded city record.

Data as of 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Boston Threshold Days: Hot, Cold and Wet Days per Year

Key Facts for Boston Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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