Hyannis Threshold Days by Year (USC00254100)

19 fixed thresholds counted per year at Hyannis (USC00254100): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Hyannis Thresholds

Hyannis: days with 10 mm (0.39 in) or more of precipitation in 52 years, most in 1930 with 23.
Hyannis: days with 25 mm (0.98 in) or more of precipitation in 49 years, most in 1977 with 8.
Hyannis: nights with a minimum temperature at or below 0 C (32 F) in 48 years, most in 1970 with 197.
Hyannis: nights with a minimum temperature at or below -10 C (14 F) in 48 years, most in 1978 with 87.
19 fixed thresholds have at least one qualifying day at Hyannis.

Days at or above 30 C (86 F)

45 years with a qualifying day

Days per year at Hyannis with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 94 in 1936.

Days at or above 30 C (86 F) per year at Hyannis
Year	Days	Decade average
1928	43	54
1929	65	54
1930	52	72.6
1931	87	72.6
1932	68	72.6
1933	78	72.6
1934	55	72.6
1935	64	72.6
1936	94	72.6
1937	83	72.6
1940	72	52
1941	57	52
1942	42	52
1943	59	52
1944	43	52
1945	40	52
1946	48	52
1947	52	52
1948	55	52
1950	41	56.2
1951	27	56.2
1952	73	56.2
1953	65	56.2
1954	59	56.2
1955	69	56.2
1956	69	56.2
1957	49	56.2
1958	54	56.2
1960	70	70
1970	70	52.3
1971	38	52.3
1975	54	52.3
1976	58	52.3
1977	42	52.3
1978	61	52.3
1979	43	52.3
1980	64	54.9
1981	40	54.9
1982	48	54.9
1983	64	54.9
1984	55	54.9
1985	60	54.9
1986	45	54.9
1987	63	54.9
1995	42	42

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

First to last qualifying date each year at Hyannis
Year	First date	Last date
1928	1928-05-01	1928-10-10
1929	1929-05-14	1929-09-04
1930	1930-04-08	1930-09-22
1931	1931-04-12	1931-09-28
1932	1932-05-12	1932-10-01
1933	1933-05-18	1933-09-18
1934	1934-05-30	1934-10-07
1935	1935-06-13	1935-09-23
1936	1936-05-05	1936-10-12
1937	1937-05-14	1937-09-22
1940	1940-05-12	1940-09-21
1941	1941-05-13	1941-09-19
1942	1942-05-26	1942-10-07
1943	1943-05-28	1943-09-13
1944	1944-05-13	1944-10-06
1945	1945-05-24	1945-09-06
1946	1946-04-20	1946-09-25
1947	1947-06-26	1947-10-20
1948	1948-05-14	1948-09-18
1950	1950-04-21	1950-10-30
1951	1951-06-16	1951-10-02
1952	1952-05-03	1952-09-30
1953	1953-05-24	1953-10-09
1954	1954-05-21	1954-10-08
1955	1955-06-20	1955-09-17
1956	1956-05-18	1956-10-12
1957	1957-05-07	1957-09-29
1958	1958-05-12	1958-10-19
1960	1960-05-13	1960-10-08
1970	1970-05-18	1970-10-06
1971	1971-06-17	1971-09-14
1975	1975-06-13	1975-10-07
1976	1976-06-02	1976-09-30
1977	1977-06-03	1977-09-08
1978	1978-05-24	1978-09-15
1979	1979-05-28	1979-09-30
1980	1980-04-21	1980-09-30
1981	1981-05-02	1981-09-20
1982	1982-06-28	1982-09-11
1983	1983-05-26	1983-09-26
1984	1984-05-23	1984-09-19
1985	1985-04-17	1985-09-18
1986	1986-05-04	1986-08-30
1987	1987-04-18	1987-10-03
1995	1995-06-14	1995-09-28

Every Fixed Threshold

Fixed thresholds at Hyannis
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	45	94	1936	42
35 C (95 F): Days	45	44	1936	6
40 C (104 F): Days	7	8	1936	5
90 F (32.2 C): Days	45	74	1936	27
100 F (37.8 C): Days	32	29	1936	3
110 F (43.3 C): Days	1	1	1940	1
0 C (32 F): Ice days (max	45	73	1978	43
0 C (32 F): Frost days (min	48	197	1970	150
-10 C (14 F): Days with min	48	87	1978	45
-20 C (-4 F): Days with min	48	28	1936	10
-30 C (-22 F): Days with min	15	5	1936	5
20 C (68 F): Tropical nights (min	37	10	1929	2
25 C (77 F): Days with min	1	1	1954	1
10 mm (0.39 in): Days with 10 mm or more rain	52	23	1930	20
25 mm (0.98 in): Days with 25 mm or more rain	49	8	1977	2
50 mm (1.97 in): Days with 50 mm or more rain	20	2	1942	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1978	1
10 cm (3.9 in): Days with 10 cm or more snowfall	32	6	1975	4
25 cm (9.8 in): Days with 25 cm or more snowfall	7	2	1975	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1928.

Download the Data

Data for Hyannis 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).

Hyannis Threshold Days by Year (USC00254100)

Key Facts for Hyannis Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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