Natl Arboretum Dc Threshold Days by Year (USC00186350)

17 fixed thresholds counted per year at Natl Arboretum Dc (USC00186350): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Natl Arboretum Dc Thresholds

Natl Arboretum Dc: days with 10 mm (0.39 in) or more of precipitation in 72 years, most in 2003 with 57.
Natl Arboretum Dc: days with 25 mm (0.98 in) or more of precipitation in 72 years, most in 2018 with 24.
Natl Arboretum Dc: days with a maximum temperature at or above 30 C (86 F) in 70 years, most in 1957 with 103.
Natl Arboretum Dc: days with a maximum temperature at or above 90 F (32.2 C) in 70 years, most in 2019 with 73.
17 fixed thresholds have at least one qualifying day at Natl Arboretum Dc.

Days at or above 30 C (86 F)

70 years with a qualifying day

Days per year at Natl Arboretum Dc with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 103 in 1957.

Days at or above 30 C (86 F) per year at Natl Arboretum Dc
Year	Days	Decade average
1949	76	76
1950	62	82.6
1951	82	82.6
1954	88	82.6
1955	80	82.6
1956	77	82.6
1957	103	82.6
1958	66	82.6
1959	103	82.6
1960	74	76.1
1961	82	76.1
1962	85	76.1
1963	74	76.1
1964	88	76.1
1965	75	76.1
1966	83	76.1
1967	56	76.1
1968	70	76.1
1969	74	76.1
1970	82	61.8
1971	67	61.8
1972	55	61.8
1973	67	61.8
1974	54	61.8
1975	58	61.8
1976	62	61.8
1977	70	61.8
1978	59	61.8
1979	44	61.8
1980	78	64.1
1981	49	64.1
1982	48	64.1
1983	77	64.1
1984	56	64.1
1985	66	64.1
1986	48	64.1
1987	81	64.1
1988	74	64.1
1990	72	74.7
1991	99	74.7
1992	44	74.7
1993	85	74.7
1994	73	74.7
1996	61	74.7
1997	58	74.7
1998	97	74.7
1999	83	74.7
2000	78	75.8
2001	90	75.8
2003	53	75.8
2004	66	75.8
2005	78	75.8
2006	69	75.8
2007	93	75.8
2008	69	75.8
2009	86	75.8
2010	94	86.6
2011	98	86.6
2012	84	86.6
2013	79	86.6
2014	76	86.6
2015	88	86.6
2016	88	86.6
2017	78	86.6
2018	85	86.6
2019	96	86.6
2020	72	67.5
2021	81	67.5
2022	78	67.5
2026	39	67.5

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

First to last qualifying date each year at Natl Arboretum Dc
Year	First date	Last date
1949	1949-04-15	1949-10-11
1950	1950-05-06	1950-11-01
1951	1951-04-29	1951-10-06
1954	1954-04-19	1954-10-14
1955	1955-05-05	1955-09-21
1956	1956-04-28	1956-09-24
1957	1957-04-21	1957-09-23
1958	1958-05-04	1958-10-10
1959	1959-04-08	1959-10-07
1960	1960-04-14	1960-09-10
1961	1961-04-25	1961-09-26
1962	1962-04-22	1962-10-13
1963	1963-04-02	1963-09-21
1964	1964-04-17	1964-09-24
1965	1965-05-03	1965-09-24
1966	1966-05-06	1966-09-11
1967	1967-04-02	1967-10-06
1968	1968-06-06	1968-09-26
1969	1969-04-27	1969-09-17
1970	1970-05-09	1970-09-27
1971	1971-05-19	1971-09-16
1972	1972-06-04	1972-09-27
1973	1973-04-23	1973-10-05
1974	1974-04-29	1974-09-14
1975	1975-05-21	1975-10-16
1976	1976-04-17	1976-09-15
1977	1977-04-13	1977-09-21
1978	1978-04-02	1978-09-20
1979	1979-05-10	1979-09-15
1980	1980-05-06	1980-09-24
1981	1981-05-26	1981-09-15
1982	1982-05-08	1982-10-03
1983	1983-04-29	1983-10-06
1984	1984-05-20	1984-09-27
1985	1985-04-20	1985-09-21
1986	1986-05-02	1986-10-03
1987	1987-05-11	1987-09-19
1988	1988-05-24	1988-09-24
1990	1990-03-13	1990-10-14
1991	1991-04-08	1991-10-05
1992	1992-04-18	1992-09-23
1993	1993-05-11	1993-09-16
1994	1994-04-16	1994-09-18
1996	1996-04-23	1996-09-11
1997	1997-05-20	1997-10-10
1998	1998-03-30	1998-10-01
1999	1999-04-09	1999-09-15
2000	2000-03-09	2000-10-07
2001	2001-04-10	2001-10-25
2003	2003-04-17	2003-09-02
2004	2004-04-19	2004-09-24
2005	2005-04-07	2005-09-24
2006	2006-05-27	2006-09-19
2007	2007-05-01	2007-10-10
2008	2008-06-02	2008-09-15
2009	2009-04-19	2009-10-10
2010	2010-04-07	2010-10-12
2011	2011-04-12	2011-10-11
2012	2012-03-24	2012-09-29
2013	2013-04-10	2013-10-07
2014	2014-04-14	2014-09-22
2015	2015-05-05	2015-09-20
2016	2016-04-27	2016-10-20
2017	2017-04-12	2017-09-28
2018	2018-04-14	2018-10-09
2019	2019-05-03	2019-10-03
2020	2020-05-16	2020-09-05
2021	2021-04-28	2021-10-05
2022	2022-04-14	2022-09-22
2026	2026-03-12	2026-08-18

Every Fixed Threshold

Fixed thresholds at Natl Arboretum Dc
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	70	103	1957	39
35 C (95 F): Days	64	35	1999	11
40 C (104 F): Days	5	3	1999	2
90 F (32.2 C): Days	70	73	2019	26
100 F (37.8 C): Days	25	14	1999	3
0 C (32 F): Ice days (max	66	28	1977	9
0 C (32 F): Frost days (min	68	121	1988	51
-10 C (14 F): Days with min	61	20	1979	9
-20 C (-4 F): Days with min	4	3	1982	2
20 C (68 F): Tropical nights (min	68	96	2018	22
25 C (77 F): Days with min	40	13	2016	2
10 mm (0.39 in): Days with 10 mm or more rain	72	57	2003	23
25 mm (0.98 in): Days with 25 mm or more rain	72	24	2018	3
50 mm (1.97 in): Days with 50 mm or more rain	57	6	2008	2
100 mm (3.94 in): Days with 100 mm or more rain	15	2	1955	1
10 cm (3.9 in): Days with 10 cm or more snowfall	36	5	1966	1
25 cm (9.8 in): Days with 25 cm or more snowfall	4	1	1966	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.

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Data for Natl Arboretum Dc 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 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Natl Arboretum Dc Threshold Days by Year (USC00186350)

Key Facts for Natl Arboretum Dc Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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