Chief Joseph Dam Threshold Days by Year (USC00451400)

17 fixed thresholds counted per year at Chief Joseph Dam (USC00451400): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Chief Joseph Dam Thresholds

Chief Joseph Dam: days with a maximum temperature at or above 30 C (86 F) in 66 years, most in 2009 with 87.
Chief Joseph Dam: days with a maximum temperature at or above 35 C (95 F) in 66 years, most in 1958 with 50.
Chief Joseph Dam: days with a maximum temperature at or above 90 F (32.2 C) in 66 years, most in 1958 with 71.
Chief Joseph Dam: days with a maximum temperature at or below 0 C (32 F) in 66 years, most in 1985 with 70.
17 fixed thresholds have at least one qualifying day at Chief Joseph Dam.

Days at or above 30 C (86 F)

66 years with a qualifying day

Days per year at Chief Joseph Dam with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 87 in 2009.

Days at or above 30 C (86 F) per year at Chief Joseph Dam
Year	Days	Decade average
1951	62	55.9
1952	52	55.9
1953	54	55.9
1955	53	55.9
1956	53	55.9
1957	48	55.9
1958	84	55.9
1959	41	55.9
1960	58	51.9
1961	68	51.9
1962	45	51.9
1963	52	51.9
1964	28	51.9
1965	42	51.9
1966	57	51.9
1967	72	51.9
1968	36	51.9
1969	61	51.9
1970	57	50.3
1971	42	50.3
1972	22	50.3
1974	49	50.3
1975	52	50.3
1976	34	50.3
1977	67	50.3
1978	52	50.3
1979	78	50.3
1980	43	61.7
1981	59	61.7
1982	57	61.7
1983	48	61.7
1984	55	61.7
1985	68	61.7
1986	74	61.7
1987	78	61.7
1988	70	61.7
1989	65	61.7
1990	68	63.9
1991	66	63.9
1992	71	63.9
1993	46	63.9
1994	80	63.9
1995	65	63.9
1996	53	63.9
1997	46	63.9
1998	82	63.9
1999	62	63.9
2000	59	70
2001	71	70
2002	66	70
2003	81	70
2004	63	70
2005	65	70
2006	77	70
2007	73	70
2008	58	70
2009	87	70
2010	50	63.3
2011	52	63.3
2012	62	63.3
2013	77	63.3
2014	60	63.3
2015	87	63.3
2016	47	63.3
2018	66	63.3
2019	69	63.3

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

First to last qualifying date each year at Chief Joseph Dam
Year	First date	Last date
1951	1951-05-22	1951-09-19
1952	1952-06-09	1952-09-27
1953	1953-06-15	1953-09-16
1955	1955-06-07	1955-09-12
1956	1956-05-16	1956-09-18
1957	1957-05-01	1957-09-26
1958	1958-05-17	1958-09-11
1959	1959-05-14	1959-09-12
1960	1960-05-11	1960-09-19
1961	1961-05-26	1961-09-18
1962	1962-06-09	1962-09-27
1963	1963-05-24	1963-09-30
1964	1964-06-23	1964-09-25
1965	1965-05-29	1965-08-20
1966	1966-05-06	1966-09-23
1967	1967-05-22	1967-09-29
1968	1968-04-30	1968-09-10
1969	1969-05-10	1969-09-13
1970	1970-05-17	1970-09-02
1971	1971-05-13	1971-09-11
1972	1972-06-01	1972-09-05
1974	1974-06-12	1974-09-25
1975	1975-06-02	1975-09-16
1976	1976-05-17	1976-09-30
1977	1977-04-24	1977-09-15
1978	1978-06-03	1978-09-03
1979	1979-05-22	1979-09-26
1980	1980-04-28	1980-09-12
1981	1981-05-01	1981-09-19
1982	1982-05-25	1982-09-09
1983	1983-05-21	1983-08-24
1984	1984-05-30	1984-09-19
1985	1985-05-17	1985-08-29
1986	1986-05-27	1986-09-04
1987	1987-04-27	1987-10-03
1988	1988-04-14	1988-09-15
1989	1989-04-07	1989-09-25
1990	1990-05-05	1990-09-29
1991	1991-06-01	1991-09-28
1992	1992-05-04	1992-09-22
1993	1993-05-11	1993-09-10
1994	1994-05-06	1994-09-27
1995	1995-05-14	1995-09-17
1996	1996-06-03	1996-09-13
1997	1997-05-14	1997-09-09
1998	1998-04-30	1998-09-17
1999	1999-05-23	1999-09-22
2000	2000-06-04	2000-09-17
2001	2001-05-12	2001-09-24
2002	2002-06-12	2002-09-19
2003	2003-05-24	2003-09-28
2004	2004-06-03	2004-09-08
2005	2005-04-26	2005-09-08
2006	2006-05-15	2006-09-28
2007	2007-05-08	2007-09-16
2008	2008-05-15	2008-09-18
2009	2009-05-17	2009-09-26
2010	2010-06-13	2010-09-28
2011	2011-06-28	2011-09-24
2012	2012-05-14	2012-09-27
2013	2013-05-06	2013-09-15
2014	2014-05-14	2014-10-06
2015	2015-04-18	2015-09-12
2016	2016-04-20	2016-09-15
2018	2018-05-13	2018-09-07
2019	2019-05-11	2019-09-07

Every Fixed Threshold

Fixed thresholds at Chief Joseph Dam
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	66	87	2009	69
35 C (95 F): Days	66	50	1958	15
40 C (104 F): Days	37	10	1992	2
45 C (113 F): Days	1	1	2015	1
90 F (32.2 C): Days	66	71	1958	42
100 F (37.8 C): Days	60	23	1998	5
110 F (43.3 C): Days	4	1	1994	1
0 C (32 F): Ice days (max	66	70	1985	33
0 C (32 F): Frost days (min	64	160	2011	139
-10 C (14 F): Days with min	63	49	1985	18
-20 C (-4 F): Days with min	29	11	1979	1
20 C (68 F): Tropical nights (min	47	9	1996	3
25 C (77 F): Days with min	1	3	1996	3
10 mm (0.39 in): Days with 10 mm or more rain	65	14	1980	8
25 mm (0.98 in): Days with 25 mm or more rain	19	2	1984	2
10 cm (3.9 in): Days with 10 cm or more snowfall	32	5	1979	3
25 cm (9.8 in): Days with 25 cm or more snowfall	1	1	1996	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1951.

Download the Data

Data for Chief Joseph Dam 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).

Chief Joseph Dam Threshold Days by Year (USC00451400)

Key Facts for Chief Joseph Dam Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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