Unionville Threshold Days by Year (USC00189030)

19 fixed thresholds counted per year at Unionville (USC00189030): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Unionville Thresholds

Unionville: nights with a minimum temperature at or below 0 C (32 F) in 56 years, most in 1988 with 164.
Unionville: nights with a minimum temperature at or below -10 C (14 F) in 56 years, most in 1963 with 40.
Unionville: nights with a minimum temperature at or above 20 C (68 F) in 56 years, most in 1959 with 34.
Unionville: days with a maximum temperature at or above 30 C (86 F) in 55 years, most in 1959 with 82.
19 fixed thresholds have at least one qualifying day at Unionville.

Days at or above 30 C (86 F)

55 years with a qualifying day

Days per year at Unionville with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 82 in 1959.

Days at or above 30 C (86 F) per year at Unionville
Year	Days	Decade average
1941	76	51.3
1942	49	51.3
1943	79	51.3
1944	67	51.3
1945	56	51.3
1946	44	51.3
1947	19	51.3
1948	23	51.3
1949	49	51.3
1950	42	61.7
1951	62	61.7
1952	58	61.7
1953	74	61.7
1954	62	61.7
1955	67	61.7
1956	46	61.7
1957	77	61.7
1958	47	61.7
1959	82	61.7
1960	44	43.7
1961	54	43.7
1962	43	43.7
1963	29	43.7
1964	52	43.7
1965	50	43.7
1966	62	43.7
1967	23	43.7
1968	41	43.7
1969	39	43.7
1970	52	34.7
1971	28	34.7
1972	30	34.7
1973	43	34.7
1974	25	34.7
1975	30	34.7
1976	30	34.7
1977	48	34.7
1978	35	34.7
1979	26	34.7
1980	64	55.6
1981	30	55.6
1982	35	55.6
1983	70	55.6
1984	43	55.6
1985	49	55.6
1986	78	55.6
1987	71	55.6
1988	76	55.6
1989	40	55.6
1990	41	59.8
1991	81	59.8
1992	28	59.8
1993	73	59.8
1994	60	59.8
1995	76	59.8

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

First to last qualifying date each year at Unionville
Year	First date	Last date
1941	1941-04-14	1941-10-07
1942	1942-04-26	1942-09-19
1943	1943-05-06	1943-09-28
1944	1944-05-04	1944-09-05
1945	1945-03-29	1945-09-29
1946	1946-04-23	1946-09-27
1947	1947-05-24	1947-09-15
1948	1948-03-21	1948-09-13
1949	1949-05-05	1949-10-11
1950	1950-06-07	1950-09-02
1951	1951-05-16	1951-10-05
1952	1952-06-04	1952-10-02
1953	1953-05-10	1953-10-03
1954	1954-05-02	1954-10-13
1955	1955-05-05	1955-09-20
1956	1956-04-28	1956-09-23
1957	1957-04-21	1957-09-22
1958	1958-05-04	1958-10-10
1959	1959-04-09	1959-10-06
1960	1960-04-23	1960-09-09
1961	1961-06-02	1961-09-25
1962	1962-04-26	1962-10-12
1963	1963-05-05	1963-09-20
1964	1964-05-19	1964-09-17
1965	1965-05-03	1965-09-22
1966	1966-05-06	1966-09-05
1967	1967-06-09	1967-08-18
1968	1968-06-06	1968-10-01
1969	1969-05-28	1969-09-17
1970	1970-05-09	1970-09-26
1971	1971-05-19	1971-09-10
1972	1972-07-02	1972-09-26
1973	1973-06-04	1973-09-27
1974	1974-04-29	1974-08-29
1975	1975-05-21	1975-08-27
1976	1976-04-16	1976-09-14
1977	1977-04-12	1977-09-19
1978	1978-06-02	1978-09-19
1979	1979-05-09	1979-09-04
1980	1980-06-01	1980-09-23
1981	1981-05-25	1981-09-15
1982	1982-05-07	1982-09-12
1983	1983-06-12	1983-09-21
1984	1984-05-22	1984-09-24
1985	1985-04-19	1985-09-20
1986	1986-05-06	1986-10-02
1987	1987-05-10	1987-08-28
1988	1988-05-23	1988-09-23
1989	1989-05-20	1989-09-21
1990	1990-04-26	1990-09-06
1991	1991-05-12	1991-09-17
1992	1992-05-22	1992-08-28
1993	1993-05-10	1993-09-15
1994	1994-04-15	1994-09-17
1995	1995-04-19	1995-10-06

Every Fixed Threshold

Fixed thresholds at Unionville
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	55	82	1959	76
35 C (95 F): Days	38	26	1988	12
90 F (32.2 C): Days	55	54	1988	44
100 F (37.8 C): Days	8	7	1953	1
0 C (32 F): Ice days (max	55	35	1978	19
0 C (32 F): Frost days (min	56	164	1988	101
-10 C (14 F): Days with min	56	40	1963	25
-20 C (-4 F): Days with min	30	12	1961	3
-30 C (-22 F): Days with min	1	1	1994	1
20 C (68 F): Tropical nights (min	56	34	1959	10
25 C (77 F): Days with min	2	2	1955	1
10 mm (0.39 in): Days with 10 mm or more rain	55	46	1994	51
25 mm (0.98 in): Days with 25 mm or more rain	55	19	1975	21
50 mm (1.97 in): Days with 50 mm or more rain	43	6	1942	6
100 mm (3.94 in): Days with 100 mm or more rain	7	1	1942	1
200 mm (7.87 in): Days with 200 mm or more rain	1	1	1972	1
10 cm (3.9 in): Days with 10 cm or more snowfall	47	8	1961	4
25 cm (9.8 in): Days with 25 cm or more snowfall	14	2	1958	1
50 cm (19.7 in): Days with 50 cm or more snowfall	1	1	1983	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1941.

Download the Data

Data for Unionville 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).

Unionville Threshold Days by Year (USC00189030)

Key Facts for Unionville Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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