Delta Threshold Days by Year (USC00052192)

15 fixed thresholds counted per year at Delta (USC00052192): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Delta Thresholds

Delta: nights with a minimum temperature at or below 0 C (32 F) in 93 years, most in 1912 with 199.
Delta: nights with a minimum temperature at or below -10 C (14 F) in 93 years, most in 1919 with 76.
Delta: days with a maximum temperature at or above 30 C (86 F) in 90 years, most in 1934 with 119.
Delta: days with a maximum temperature at or above 35 C (95 F) in 90 years, most in 1900 with 69.
15 fixed thresholds have at least one qualifying day at Delta.

Days at or above 30 C (86 F)

90 years with a qualifying day

Days per year at Delta with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 119 in 1934.

Days at or above 30 C (86 F) per year at Delta
Year	Days	Decade average
1893	97	98
1894	92	98
1895	104	98
1897	99	98
1898	100	98
1899	96	98
1900	112	90.2
1901	110	90.2
1902	96	90.2
1907	62	90.2
1908	79	90.2
1909	82	90.2
1910	111	85.6
1911	74	85.6
1912	70	85.6
1913	95	85.6
1914	81	85.6
1915	89	85.6
1916	74	85.6
1917	84	85.6
1918	80	85.6
1919	98	85.6
1920	79	78.9
1921	85	78.9
1922	107	78.9
1923	70	78.9
1924	85	78.9
1925	64	78.9
1926	78	78.9
1927	62	78.9
1928	89	78.9
1929	70	78.9
1930	92	97.3
1931	96	97.3
1932	81	97.3
1933	97	97.3
1934	119	97.3
1935	98	97.3
1936	103	97.3
1937	97	97.3
1938	99	97.3
1939	91	97.3
1940	104	102
1941	88	102
1942	114	102
1943	103	102
1944	112	102
1945	98	102
1946	99	102
1947	91	102
1948	106	102
1949	105	102
1950	96	97.4
1951	96	97.4
1952	100	97.4
1953	103	97.4
1954	104	97.4
1955	92	97.4
1956	108	97.4
1957	73	97.4
1958	104	97.4
1959	98	97.4
1960	95	83.3
1961	93	83.3
1962	91	83.3
1963	81	83.3
1964	79	83.3
1965	66	83.3
1966	99	83.3
1967	76	83.3
1968	58	83.3
1969	95	83.3
1970	89	95.6
1971	90	95.6
1974	103	95.6
1977	99	95.6
1979	97	95.6
1980	101	88
1981	96	88
1982	74	88
1983	90	88
1984	79	88
1990	97	74.5
1991	77	74.5
1992	57	74.5
1993	43	74.5
1994	97	74.5
1995	70	74.5
1996	94	74.5
1999	61	74.5

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

First to last qualifying date each year at Delta
Year	First date	Last date
1893	1893-05-13	1893-09-16
1894	1894-04-25	1894-09-24
1895	1895-04-30	1895-09-28
1897	1897-04-18	1897-09-10
1898	1898-04-26	1898-09-26
1899	1899-05-11	1899-10-06
1900	1900-05-08	1900-09-22
1901	1901-05-01	1901-10-03
1902	1902-04-30	1902-09-17
1907	1907-05-19	1907-09-24
1908	1908-06-09	1908-09-23
1909	1909-06-03	1909-09-28
1910	1910-04-27	1910-10-11
1911	1911-05-05	1911-09-25
1912	1912-05-17	1912-09-19
1913	1913-05-16	1913-09-29
1914	1914-05-08	1914-09-28
1915	1915-05-12	1915-09-23
1916	1916-05-05	1916-09-21
1917	1917-06-09	1917-10-10
1918	1918-06-02	1918-09-22
1919	1919-04-23	1919-09-18
1920	1920-05-20	1920-10-04
1921	1921-05-27	1921-09-28
1922	1922-05-06	1922-10-04
1923	1923-05-10	1923-09-11
1924	1924-05-12	1924-09-08
1925	1925-05-18	1925-08-30
1926	1926-05-22	1926-09-22
1927	1927-05-15	1927-09-23
1928	1928-04-30	1928-10-08
1929	1929-05-15	1929-09-01
1930	1930-04-08	1930-09-21
1931	1931-05-14	1931-09-17
1932	1932-06-11	1932-09-17
1933	1933-05-20	1933-10-01
1934	1934-04-21	1934-09-19
1935	1935-05-26	1935-10-10
1936	1936-05-03	1936-09-25
1937	1937-04-15	1937-09-20
1938	1938-05-14	1938-09-29
1939	1939-04-28	1939-09-23
1940	1940-05-03	1940-09-27
1941	1941-05-08	1941-09-19
1942	1942-05-21	1942-10-11
1943	1943-04-23	1943-09-26
1944	1944-05-12	1944-10-09
1945	1945-05-18	1945-10-09
1946	1946-04-25	1946-09-29
1947	1947-05-02	1947-10-09
1948	1948-05-14	1948-10-03
1949	1949-04-24	1949-10-04
1950	1950-05-21	1950-10-13
1951	1951-05-05	1951-09-27
1952	1952-05-02	1952-10-03
1953	1953-04-22	1953-10-01
1954	1954-05-08	1954-10-01
1955	1955-05-06	1955-09-16
1956	1956-05-04	1956-10-05
1957	1957-05-05	1957-10-01
1958	1958-05-05	1958-09-22
1959	1959-04-05	1959-09-14
1960	1960-05-10	1960-09-29
1961	1961-05-10	1961-08-29
1962	1962-04-15	1962-09-19
1963	1963-05-06	1963-10-04
1964	1964-05-13	1964-09-13
1965	1965-05-17	1965-08-28
1966	1966-05-04	1966-09-25
1967	1967-05-09	1967-09-24
1968	1968-05-29	1968-09-11
1969	1969-04-22	1969-09-29
1970	1970-05-05	1970-09-18
1971	1971-05-26	1971-09-14
1974	1974-05-08	1974-09-20
1977	1977-05-09	1977-10-04
1979	1979-05-19	1979-10-09
1980	1980-05-21	1980-10-09
1981	1981-04-29	1981-09-30
1982	1982-05-24	1982-09-23
1983	1983-05-24	1983-09-19
1984	1984-05-11	1984-09-18
1990	1990-05-23	1990-09-16
1991	1991-05-19	1991-09-29
1992	1992-04-30	1992-10-03
1993	1993-05-26	1993-08-25
1994	1994-05-31	1994-09-29
1995	1995-06-13	1995-09-18
1996	1996-05-12	1996-09-11
1999	1999-05-23	1999-09-09

Every Fixed Threshold

Fixed thresholds at Delta
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	90	119	1934	61
35 C (95 F): Days	90	69	1900	7
40 C (104 F): Days	13	17	1900	6
90 F (32.2 C): Days	90	95	1900	29
100 F (37.8 C): Days	63	42	1900	3
0 C (32 F): Ice days (max	89	52	1930	4
0 C (32 F): Frost days (min	93	199	1912	164
-10 C (14 F): Days with min	93	76	1919	26
-20 C (-4 F): Days with min	68	20	1930	4
-30 C (-22 F): Days with min	8	3	1913	2
20 C (68 F): Tropical nights (min	15	4	1907	1
10 mm (0.39 in): Days with 10 mm or more rain	85	9	1917	5
25 mm (0.98 in): Days with 25 mm or more rain	21	6	1893	2
50 mm (1.97 in): Days with 50 mm or more rain	2	4	1893	1
10 cm (3.9 in): Days with 10 cm or more snowfall	32	4	1913	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1893.

Download the Data

Data for Delta 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).

Delta Threshold Days by Year (USC00052192)

Key Facts for Delta Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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