Imperial Threshold Days by Year (USC00143946)

17 fixed thresholds counted per year at Imperial (USC00143946): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Imperial Thresholds

Imperial: days with 10 mm (0.39 in) or more of precipitation in 42 years, most in 1944 with 27.
Imperial: days with 25 mm (0.98 in) or more of precipitation in 42 years, most in 1958 with 9.
Imperial: days with 10 cm (3.9 in) or more of snowfall in 35 years, most in 1948 with 6.
Imperial: days with 50 mm (1.97 in) or more of precipitation in 20 years, most in 1946 with 3.
17 fixed thresholds have at least one qualifying day at Imperial.

Days at or above 30 C (86 F)

18 years with a qualifying day

Days per year at Imperial with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 115 in 1963.

Days at or above 30 C (86 F) per year at Imperial
Year	Days	Decade average
1961	83	92.5
1962	94	92.5
1963	115	92.5
1964	105	92.5
1965	92	92.5
1966	89	92.5
1967	85	92.5
1969	77	92.5
1970	100	90
1971	83	90
1972	76	90
1973	70	90
1975	100	90
1976	88	90
1977	93	90
1978	104	90
1979	96	90
1980	98	98

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

First to last qualifying date each year at Imperial
Year	First date	Last date
1961	1961-04-19	1961-10-07
1962	1962-04-20	1962-10-14
1963	1963-03-28	1963-10-10
1964	1964-04-01	1964-10-16
1965	1965-04-20	1965-10-10
1966	1966-05-03	1966-10-13
1967	1967-04-04	1967-10-21
1969	1969-05-26	1969-10-03
1970	1970-05-05	1970-10-06
1971	1971-03-31	1971-09-29
1972	1972-03-11	1972-10-10
1973	1973-06-02	1973-10-23
1975	1975-04-24	1975-10-22
1976	1976-03-25	1976-10-11
1977	1977-05-07	1977-10-26
1978	1978-03-31	1978-10-20
1979	1979-04-20	1979-10-27
1980	1980-04-21	1980-11-09

Every Fixed Threshold

Fixed thresholds at Imperial
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	18	115	1963	98
35 C (95 F): Days	18	62	1980	62
40 C (104 F): Days	12	18	1980	18
90 F (32.2 C): Days	18	88	1963	80
100 F (37.8 C): Days	17	31	1978	29
0 C (32 F): Ice days (max	18	43	1978	28
0 C (32 F): Frost days (min	17	160	1979	158
-10 C (14 F): Days with min	17	50	1978	37
-20 C (-4 F): Days with min	17	15	1979	4
20 C (68 F): Tropical nights (min	17	31	1963	23
25 C (77 F): Days with min	7	4	1971	3
10 mm (0.39 in): Days with 10 mm or more rain	42	27	1944	12
25 mm (0.98 in): Days with 25 mm or more rain	42	9	1958	2
50 mm (1.97 in): Days with 50 mm or more rain	20	3	1946	1
100 mm (3.94 in): Days with 100 mm or more rain	1	0	n/a	1
10 cm (3.9 in): Days with 10 cm or more snowfall	35	6	1948	3
25 cm (9.8 in): Days with 25 cm or more snowfall	1	1	1970	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1961.

Download the Data

Data for Imperial 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).

Imperial Threshold Days by Year (USC00143946)

Key Facts for Imperial Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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