Washington Dulles Intl AP Threshold Days by Year (USW00093738)

19 fixed thresholds counted per year at Washington Dulles Intl AP (USW00093738): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Washington Dulles Intl AP Thresholds

Washington Dulles Intl AP: days with a maximum temperature at or above 30 C (86 F) in 64 years, most in 2007 with 99.
Washington Dulles Intl AP: days with a maximum temperature at or above 90 F (32.2 C) in 64 years, most in 2010 with 58.
Washington Dulles Intl AP: nights with a minimum temperature at or below 0 C (32 F) in 64 years, most in 1976 with 145.
Washington Dulles Intl AP: nights with a minimum temperature at or above 20 C (68 F) in 64 years, most in 2018 with 66.
19 fixed thresholds have at least one qualifying day at Washington Dulles Intl AP.

Days at or above 30 C (86 F)

64 years with a qualifying day

Days per year at Washington Dulles Intl AP with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 99 in 2007.

Days at or above 30 C (86 F) per year at Washington Dulles Intl AP
Year	Days	Decade average
1963	55	55.1
1964	64	55.1
1965	60	55.1
1966	62	55.1
1967	38	55.1
1968	48	55.1
1969	59	55.1
1970	62	53
1971	55	53
1972	46	53
1973	59	53
1974	37	53
1975	47	53
1976	44	53
1977	71	53
1978	63	53
1979	46	53
1980	78	65
1981	52	65
1982	59	65
1983	66	65
1984	41	65
1985	65	65
1986	81	65
1987	81	65
1988	70	65
1989	57	65
1990	62	64.7
1991	91	64.7
1992	36	64.7
1993	84	64.7
1994	76	64.7
1995	70	64.7
1996	34	64.7
1997	50	64.7
1998	81	64.7
1999	63	64.7
2000	39	60.9
2001	48	60.9
2002	70	60.9
2003	38	60.9
2004	53	60.9
2005	80	60.9
2006	62	60.9
2007	99	60.9
2008	57	60.9
2009	63	60.9
2010	87	68.7
2011	72	68.7
2012	73	68.7
2013	61	68.7
2014	33	68.7
2015	65	68.7
2016	78	68.7
2017	65	68.7
2018	67	68.7
2019	86	68.7
2020	68	74.1
2021	71	74.1
2022	70	74.1
2023	82	74.1
2024	79	74.1
2025	64	74.1
2026	85	74.1

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

First to last qualifying date each year at Washington Dulles Intl AP
Year	First date	Last date
1963	1963-05-09	1963-10-07
1964	1964-05-07	1964-09-17
1965	1965-05-03	1965-09-23
1966	1966-05-06	1966-09-05
1967	1967-04-02	1967-10-05
1968	1968-06-06	1968-09-25
1969	1969-04-27	1969-09-17
1970	1970-05-09	1970-09-26
1971	1971-04-13	1971-09-10
1972	1972-06-04	1972-09-26
1973	1973-04-22	1973-09-07
1974	1974-04-29	1974-09-13
1975	1975-05-21	1975-10-14
1976	1976-04-16	1976-09-14
1977	1977-04-11	1977-09-19
1978	1978-05-20	1978-09-21
1979	1979-05-09	1979-10-21
1980	1980-05-05	1980-09-23
1981	1981-04-03	1981-10-01
1982	1982-05-07	1982-09-18
1983	1983-04-28	1983-09-20
1984	1984-05-19	1984-09-24
1985	1985-04-19	1985-09-20
1986	1986-03-30	1986-10-02
1987	1987-04-22	1987-09-17
1988	1988-05-23	1988-09-23
1989	1989-03-28	1989-10-15
1990	1990-03-12	1990-10-09
1991	1991-04-08	1991-09-18
1992	1992-05-02	1992-09-22
1993	1993-05-10	1993-09-15
1994	1994-04-19	1994-09-17
1995	1995-04-19	1995-10-06
1996	1996-04-22	1996-09-08
1997	1997-05-19	1997-09-07
1998	1998-03-29	1998-09-30
1999	1999-05-29	1999-09-09
2000	2000-05-05	2000-09-20
2001	2001-04-09	2001-08-31
2002	2002-04-16	2002-10-05
2003	2003-06-12	2003-09-01
2004	2004-04-18	2004-09-23
2005	2005-04-06	2005-09-23
2006	2006-05-28	2006-08-29
2007	2007-04-23	2007-10-09
2008	2008-06-05	2008-09-14
2009	2009-04-25	2009-10-09
2010	2010-04-05	2010-10-11
2011	2011-04-20	2011-09-14
2012	2012-04-16	2012-09-08
2013	2013-04-10	2013-10-06
2014	2014-05-08	2014-09-11
2015	2015-05-12	2015-09-19
2016	2016-05-25	2016-10-19
2017	2017-04-11	2017-10-10
2018	2018-04-13	2018-10-04
2019	2019-05-02	2019-10-02
2020	2020-05-15	2020-09-04
2021	2021-04-28	2021-09-18
2022	2022-04-13	2022-09-21
2023	2023-04-05	2023-10-28
2024	2024-04-28	2024-09-20
2025	2025-05-16	2025-09-19
2026	2026-03-11	2026-10-14

Every Fixed Threshold

Fixed thresholds at Washington Dulles Intl AP
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	64	99	2007	85
35 C (95 F): Days	54	23	1993	9
40 C (104 F): Days	3	1	1983	1
90 F (32.2 C): Days	64	58	2010	31
100 F (37.8 C): Days	22	5	1988	3
0 C (32 F): Ice days (max	62	31	1977	12
0 C (32 F): Frost days (min	64	145	1976	61
-10 C (14 F): Days with min	62	33	1977	14
-20 C (-4 F): Days with min	17	5	1979	2
20 C (68 F): Tropical nights (min	64	66	2018	64
25 C (77 F): Days with min	10	2	2010	2
10 mm (0.39 in): Days with 10 mm or more rain	64	58	2018	35
25 mm (0.98 in): Days with 25 mm or more rain	64	24	1996	8
50 mm (1.97 in): Days with 50 mm or more rain	52	5	1963	1
100 mm (3.94 in): Days with 100 mm or more rain	11	1	1966	1
200 mm (7.87 in): Days with 200 mm or more rain	1	1	1972	1
10 cm (3.9 in): Days with 10 cm or more snowfall	55	6	1966	1
25 cm (9.8 in): Days with 25 cm or more snowfall	14	2	1967	1
50 cm (19.7 in): Days with 50 cm or more snowfall	3	1	1983	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1963.

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Data for Washington Dulles Intl AP 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).

Washington Dulles Intl AP Threshold Days by Year (USW00093738)

Key Facts for Washington Dulles Intl AP Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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