Boysen Dam Threshold Days by Year (USC00481000)

17 fixed thresholds counted per year at Boysen Dam (USC00481000): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Boysen Dam Thresholds

Boysen Dam: days with 10 mm (0.39 in) or more of precipitation in 74 years, most in 1998 with 12.
Boysen Dam: nights with a minimum temperature at or below 0 C (32 F) in 70 years, most in 2013 with 190.
Boysen Dam: nights with a minimum temperature at or below -10 C (14 F) in 70 years, most in 2020 with 100.
Boysen Dam: nights with a minimum temperature at or below -20 C (-4 F) in 68 years, most in 1993 with 37.
17 fixed thresholds have at least one qualifying day at Boysen Dam.

Days at or above 30 C (86 F)

67 years with a qualifying day

Days per year at Boysen Dam with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 89 in 1953.

Days at or above 30 C (86 F) per year at Boysen Dam
Year	Days	Decade average
1949	64	64
1950	42	63.8
1951	40	63.8
1952	69	63.8
1953	89	63.8
1954	53	63.8
1955	63	63.8
1956	73	63.8
1957	64	63.8
1958	62	63.8
1959	83	63.8
1960	74	63.6
1961	72	63.6
1962	54	63.6
1963	66	63.6
1964	65	63.6
1965	50	63.6
1966	74	63.6
1967	62	63.6
1968	51	63.6
1969	68	63.6
1970	78	65
1971	78	65
1972	52	65
1973	67	65
1974	65	65
1977	63	65
1978	57	65
1979	60	65
1980	63	65
1981	56	65
1983	63	65
1988	85	65
1989	58	65
1990	76	55.5
1991	62	55.5
1992	44	55.5
1993	29	55.5
1998	66	55.5
1999	56	55.5
2000	70	66.5
2001	79	66.5
2002	65	66.5
2003	64	66.5
2004	34	66.5
2005	56	66.5
2006	82	66.5
2007	80	66.5
2008	70	66.5
2009	65	66.5
2010	55	69.1
2011	73	69.1
2012	83	69.1
2013	84	69.1
2014	51	69.1
2015	69	69.1
2016	75	69.1
2017	62	69.1
2018	68	69.1
2019	71	69.1
2020	80	76.1
2021	82	76.1
2022	79	76.1
2023	50	76.1
2024	81	76.1
2025	81	76.1
2026	80	76.1

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

First to last qualifying date each year at Boysen Dam
Year	First date	Last date
1949	1949-06-10	1949-09-24
1950	1950-06-05	1950-09-06
1951	1951-06-15	1951-09-10
1952	1952-05-03	1952-09-27
1953	1953-06-09	1953-09-28
1954	1954-05-19	1954-10-08
1955	1955-05-31	1955-08-30
1956	1956-05-19	1956-09-21
1957	1957-06-04	1957-09-07
1958	1958-05-21	1958-09-22
1959	1959-06-04	1959-09-15
1960	1960-05-12	1960-09-06
1961	1961-06-07	1961-08-28
1962	1962-06-13	1962-09-19
1963	1963-06-13	1963-10-01
1964	1964-05-16	1964-09-09
1965	1965-06-21	1965-08-29
1966	1966-05-05	1966-09-24
1967	1967-05-22	1967-09-26
1968	1968-06-02	1968-09-02
1969	1969-05-25	1969-09-29
1970	1970-05-17	1970-09-04
1971	1971-05-28	1971-10-10
1972	1972-05-14	1972-08-29
1973	1973-05-18	1973-09-08
1974	1974-06-13	1974-09-10
1977	1977-06-01	1977-09-11
1978	1978-05-16	1978-09-08
1979	1979-06-05	1979-09-17
1980	1980-05-23	1980-10-01
1981	1981-06-07	1981-09-20
1983	1983-06-22	1983-09-10
1988	1988-05-13	1988-09-10
1989	1989-05-28	1989-09-06
1990	1990-06-04	1990-09-15
1991	1991-06-12	1991-09-06
1992	1992-05-07	1992-09-24
1993	1993-06-21	1993-09-12
1998	1998-05-30	1998-09-17
1999	1999-06-20	1999-08-31
2000	2000-05-05	2000-09-17
2001	2001-05-14	2001-09-29
2002	2002-05-31	2002-09-06
2003	2003-05-26	2003-09-05
2004	2004-06-04	2004-09-13
2005	2005-06-17	2005-09-09
2006	2006-05-18	2006-09-15
2007	2007-04-29	2007-09-22
2008	2008-05-19	2008-09-27
2009	2009-05-19	2009-09-27
2010	2010-06-22	2010-09-29
2011	2011-06-06	2011-10-02
2012	2012-04-24	2012-09-16
2013	2013-05-14	2013-09-08
2014	2014-05-27	2014-09-27
2015	2015-06-09	2015-09-27
2016	2016-06-06	2016-09-21
2017	2017-06-02	2017-09-13
2018	2018-05-26	2018-09-19
2019	2019-06-07	2019-09-20
2020	2020-05-19	2020-09-25
2021	2021-05-01	2021-09-28
2022	2022-05-28	2022-09-20
2023	2023-07-02	2023-09-28
2024	2024-06-06	2024-10-03
2025	2025-05-13	2025-10-04
2026	2026-05-12	2026-10-07

Every Fixed Threshold

Fixed thresholds at Boysen Dam
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	67	89	1953	80
35 C (95 F): Days	67	38	2012	38
40 C (104 F): Days	8	4	1954	5
90 F (32.2 C): Days	67	69	2022	57
100 F (37.8 C): Days	42	12	2007	14
0 C (32 F): Ice days (max	67	90	2023	10
0 C (32 F): Frost days (min	70	190	2013	86
-10 C (14 F): Days with min	70	100	2020	18
-20 C (-4 F): Days with min	68	37	1993	3
-30 C (-22 F): Days with min	26	12	1979	2
20 C (68 F): Tropical nights (min	54	14	1988	17
25 C (77 F): Days with min	1	1	1954	1
10 mm (0.39 in): Days with 10 mm or more rain	74	12	1998	1
25 mm (0.98 in): Days with 25 mm or more rain	35	3	1963	1
50 mm (1.97 in): Days with 50 mm or more rain	7	1	1957	1
10 cm (3.9 in): Days with 10 cm or more snowfall	24	3	2018	1
25 cm (9.8 in): Days with 25 cm or more snowfall	4	1	1991	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1949.

Download the Data

Data for Boysen 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 2026-10-17. Last revised 17 October 2026 (2026-10-17).

Boysen Dam Threshold Days by Year (USC00481000)

Key Facts for Boysen Dam Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

Related