Alliston Threshold Days by Year (CA008300100)

14 fixed thresholds counted per year at Alliston (CA008300100): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Alliston Thresholds

Alliston: nights with a minimum temperature at or below 0 C (32 F) in 46 years, most in 1956 with 190.
Alliston: nights with a minimum temperature at or below -10 C (14 F) in 46 years, most in 1972 with 75.
Alliston: days with a maximum temperature at or below 0 C (32 F) in 44 years, most in 1965 with 92.
Alliston: days with 10 mm (0.39 in) or more of precipitation in 43 years, most in 1979 with 56.
14 fixed thresholds have at least one qualifying day at Alliston.

Days at or above 30 C (86 F)

38 years with a qualifying day

Days per year at Alliston with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 21 in 1937.

Days at or above 30 C (86 F) per year at Alliston
Year	Days	Decade average
1936	1	10
1937	21	10
1938	6	10
1939	12	10
1940	8	6.6
1941	4	6.6
1942	6	6.6
1944	13	6.6
1945	7	6.6
1946	4	6.6
1947	8	6.6
1948	2	6.6
1949	7	6.6
1950	1	2.5
1952	5	2.5
1953	1	2.5
1955	5	2.5
1957	1	2.5
1959	2	2.5
1960	2	1.5
1961	2	1.5
1962	1	1.5
1963	2	1.5
1965	2	1.5
1967	1	1.5
1968	1	1.5
1969	1	1.5
1970	6	4.7
1971	1	4.7
1972	2	4.7
1973	1	4.7
1974	1	4.7
1975	10	4.7
1976	5	4.7
1977	4	4.7
1978	2	4.7
1979	15	4.7
1980	1	1

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

First to last qualifying date each year at Alliston
Year	First date	Last date
1936	1936-07-11	1936-07-11
1937	1937-06-01	1937-09-04
1938	1938-06-22	1938-08-18
1939	1939-06-12	1939-08-24
1940	1940-07-07	1940-08-19
1941	1941-06-19	1941-06-22
1942	1942-06-11	1942-09-02
1944	1944-06-28	1944-08-17
1945	1945-06-15	1945-09-08
1946	1946-06-27	1946-08-10
1947	1947-06-29	1947-09-11
1948	1948-06-30	1948-07-01
1949	1949-06-17	1949-08-07
1950	1950-06-10	1950-06-10
1952	1952-07-08	1952-08-29
1953	1953-07-28	1953-07-28
1955	1955-07-01	1955-08-05
1957	1957-06-03	1957-06-03
1959	1959-07-22	1959-07-28
1960	1960-08-19	1960-08-29
1961	1961-08-12	1961-08-13
1962	1962-06-16	1962-06-16
1963	1963-07-26	1963-07-27
1965	1965-08-08	1965-09-23
1967	1967-06-05	1967-06-05
1968	1968-07-09	1968-07-09
1969	1969-06-28	1969-06-28
1970	1970-07-25	1970-08-16
1971	1971-08-10	1971-08-10
1972	1972-07-13	1972-07-16
1973	1973-07-08	1973-07-08
1974	1974-08-12	1974-08-12
1975	1975-06-24	1975-08-12
1976	1976-06-16	1976-08-23
1977	1977-05-22	1977-08-29
1978	1978-08-12	1978-08-17
1979	1979-06-16	1979-07-24
1980	1980-06-26	1980-06-26

Every Fixed Threshold

Fixed thresholds at Alliston
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	38	21	1937	1
35 C (95 F): Days	1	2	1944	2
90 F (32.2 C): Days	15	9	1937	2
0 C (32 F): Ice days (max	44	92	1965	62
0 C (32 F): Frost days (min	46	190	1956	135
-10 C (14 F): Days with min	46	75	1972	43
-20 C (-4 F): Days with min	42	15	1948	2
20 C (68 F): Tropical nights (min	26	8	1944	1
10 mm (0.39 in): Days with 10 mm or more rain	43	56	1979	51
25 mm (0.98 in): Days with 25 mm or more rain	42	17	1979	14
50 mm (1.97 in): Days with 50 mm or more rain	17	2	1938	1
100 mm (3.94 in): Days with 100 mm or more rain	1	1	1971	1
10 cm (3.9 in): Days with 10 cm or more snowfall	43	16	1956	8
25 cm (9.8 in): Days with 25 cm or more snowfall	17	3	1956	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1936.

Download the Data

Data for Alliston 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).

Alliston Threshold Days by Year (CA008300100)

Key Facts for Alliston Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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