Thoreau Threshold Days by Year (USC00298830)

13 fixed thresholds counted per year at Thoreau (USC00298830): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Thoreau Thresholds

Thoreau: days with 10 mm (0.39 in) or more of precipitation in 38 years, most in 1986 with 12.
Thoreau: days with 10 cm (3.9 in) or more of snowfall in 32 years, most in 1961 with 5.
Thoreau: days with a maximum temperature at or above 30 C (86 F) in 28 years, most in 1980 with 63.
Thoreau: days with a maximum temperature at or above 90 F (32.2 C) in 28 years, most in 1980 with 33.
13 fixed thresholds have at least one qualifying day at Thoreau.

Days at or above 30 C (86 F)

28 years with a qualifying day

Days per year at Thoreau with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 63 in 1980.

Days at or above 30 C (86 F) per year at Thoreau
Year	Days	Decade average
1964	24	28.5
1965	23	28.5
1966	32	28.5
1967	20	28.5
1968	30	28.5
1969	42	28.5
1970	39	40.4
1971	45	40.4
1972	40	40.4
1973	34	40.4
1974	46	40.4
1975	28	40.4
1976	29	40.4
1977	41	40.4
1978	53	40.4
1979	49	40.4
1980	63	43.3
1981	38	43.3
1982	36	43.3
1983	32	43.3
1984	38	43.3
1985	56	43.3
1986	40	43.3
1987	44	43.3
1988	31	43.3
1989	55	43.3
1990	43	34
1991	25	34

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

First to last qualifying date each year at Thoreau
Year	First date	Last date
1964	1964-05-24	1964-08-10
1965	1965-06-21	1965-08-27
1966	1966-06-14	1966-08-08
1967	1967-06-22	1967-08-25
1968	1968-06-13	1968-09-08
1969	1969-05-26	1969-08-27
1970	1970-05-18	1970-08-30
1971	1971-06-15	1971-09-12
1972	1972-06-15	1972-08-22
1973	1973-06-09	1973-08-27
1974	1974-05-26	1974-09-10
1975	1975-06-13	1975-09-01
1976	1976-06-19	1976-08-18
1977	1977-06-11	1977-09-09
1978	1978-05-14	1978-08-28
1979	1979-06-12	1979-09-08
1980	1980-06-07	1980-09-18
1981	1981-06-07	1981-08-30
1982	1982-06-12	1982-09-03
1983	1983-06-17	1983-09-17
1984	1984-05-12	1984-09-09
1985	1985-06-07	1985-09-06
1986	1986-05-26	1986-09-06
1987	1987-06-11	1987-08-31
1988	1988-05-15	1988-09-08
1989	1989-05-06	1989-09-03
1990	1990-05-22	1990-09-13
1991	1991-06-08	1991-09-02

Every Fixed Threshold

Fixed thresholds at Thoreau
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	28	63	1980	25
35 C (95 F): Days	15	8	1990	8
90 F (32.2 C): Days	28	33	1980	3
0 C (32 F): Ice days (max	28	18	1966	4
0 C (32 F): Frost days (min	28	189	1970	172
-10 C (14 F): Days with min	28	43	1964	33
-20 C (-4 F): Days with min	14	5	1971	4
20 C (68 F): Tropical nights (min	2	2	1990	2
10 mm (0.39 in): Days with 10 mm or more rain	38	12	1986	6
25 mm (0.98 in): Days with 25 mm or more rain	16	2	1954	1
50 mm (1.97 in): Days with 50 mm or more rain	1	1	1984	1
10 cm (3.9 in): Days with 10 cm or more snowfall	32	5	1961	2
25 cm (9.8 in): Days with 25 cm or more snowfall	4	1	1960	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1964.

Download the Data

Data for Thoreau 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).

Thoreau Threshold Days by Year (USC00298830)

Key Facts for Thoreau Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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