Conowingo Dam Threshold Days by Year (USC00182060)

17 fixed thresholds counted per year at Conowingo Dam (USC00182060): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Conowingo Dam Thresholds

Conowingo Dam: days with 10 mm (0.39 in) or more of precipitation in 72 years, most in 2018 with 61.
Conowingo Dam: days with 25 mm (0.98 in) or more of precipitation in 72 years, most in 2018 with 24.
Conowingo Dam: days with a maximum temperature at or above 30 C (86 F) in 66 years, most in 1991 with 102.
Conowingo Dam: days with a maximum temperature at or above 90 F (32.2 C) in 66 years, most in 1991 with 74.
17 fixed thresholds have at least one qualifying day at Conowingo Dam.

Days at or above 30 C (86 F)

66 years with a qualifying day

Days per year at Conowingo Dam with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 102 in 1991.

Days at or above 30 C (86 F) per year at Conowingo Dam
Year	Days	Decade average
1936	55	49.8
1937	47	49.8
1938	46	49.8
1939	51	49.8
1940	35	42
1949	49	42
1950	29	49.4
1951	48	49.4
1952	51	49.4
1953	51	49.4
1954	49	49.4
1955	56	49.4
1956	44	49.4
1957	65	49.4
1958	37	49.4
1959	64	49.4
1960	33	47.9
1961	54	47.9
1962	53	47.9
1963	50	47.9
1964	35	47.9
1965	50	47.9
1966	70	47.9
1967	27	47.9
1968	57	47.9
1969	50	47.9
1970	49	47.2
1971	46	47.2
1973	55	47.2
1974	45	47.2
1975	44	47.2
1979	44	47.2
1980	68	52.7
1981	35	52.7
1983	64	52.7
1984	34	52.7
1985	52	52.7
1986	44	52.7
1987	60	52.7
1988	69	52.7
1989	48	52.7
1991	102	83
1995	82	83
1996	74	83
1997	73	83
1998	84	83
2002	96	81.5
2006	67	81.5
2007	86	81.5
2008	77	81.5
2011	66	41.3
2012	45	41.3
2013	24	41.3
2014	19	41.3
2015	30	41.3
2016	51	41.3
2017	31	41.3
2018	51	41.3
2019	55	41.3
2020	56	52
2021	57	52
2022	57	52
2023	44	52
2024	57	52
2025	44	52
2026	49	52

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

First to last qualifying date each year at Conowingo Dam
Year	First date	Last date
1936	1936-05-08	1936-09-12
1937	1937-05-22	1937-09-04
1938	1938-04-20	1938-09-15
1939	1939-04-25	1939-10-10
1940	1940-05-14	1940-09-21
1949	1949-05-06	1949-09-05
1950	1950-06-07	1950-09-02
1951	1951-05-16	1951-10-05
1952	1952-06-06	1952-09-14
1953	1953-05-18	1953-09-05
1954	1954-05-31	1954-10-13
1955	1955-05-05	1955-09-01
1956	1956-05-13	1956-09-23
1957	1957-04-21	1957-09-22
1958	1958-06-09	1958-09-26
1959	1959-04-08	1959-10-05
1960	1960-04-23	1960-09-09
1961	1961-04-24	1961-09-25
1962	1962-04-25	1962-10-12
1963	1963-04-03	1963-09-12
1964	1964-04-17	1964-09-23
1965	1965-05-03	1965-09-23
1966	1966-05-06	1966-09-05
1967	1967-04-15	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	1971-05-20	1971-09-10
1973	1973-06-04	1973-09-07
1974	1974-04-29	1974-09-13
1975	1975-05-21	1975-10-14
1979	1979-05-08	1979-09-06
1980	1980-05-05	1980-09-22
1981	1981-05-24	1981-09-14
1983	1983-06-06	1983-09-20
1984	1984-05-22	1984-09-04
1985	1985-04-19	1985-09-10
1986	1986-05-05	1986-09-30
1987	1987-05-10	1987-08-21
1988	1988-05-29	1988-09-24
1989	1989-05-25	1989-09-21
1991	1991-04-07	1991-10-04
1995	1995-05-24	1995-09-15
1996	1996-04-22	1996-09-10
1997	1997-05-19	1997-10-10
1998	1998-03-27	1998-09-27
2002	2002-04-16	2002-10-06
2006	2006-05-29	2006-09-01
2007	2007-05-01	2007-10-10
2008	2008-04-19	2008-09-15
2011	2011-05-25	2011-09-05
2012	2012-05-27	2012-09-08
2013	2013-04-11	2013-09-12
2014	2014-06-18	2014-09-07
2015	2015-06-01	2015-09-10
2016	2016-05-27	2016-09-15
2017	2017-04-17	2017-09-28
2018	2018-05-03	2018-09-27
2019	2019-05-20	2019-10-03
2020	2020-06-04	2020-09-05
2021	2021-04-29	2021-09-16
2022	2022-05-22	2022-09-06
2023	2023-04-14	2023-09-09
2024	2024-04-30	2024-09-21
2025	2025-05-18	2025-08-20
2026	2026-04-15	2026-08-20

Every Fixed Threshold

Fixed thresholds at Conowingo Dam
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	66	102	1991	49
35 C (95 F): Days	56	30	2002	6
40 C (104 F): Days	7	2	1991	1
90 F (32.2 C): Days	66	74	1991	19
100 F (37.8 C): Days	20	11	2002	1
0 C (32 F): Ice days (max	65	32	2014	11
0 C (32 F): Frost days (min	63	141	1988	58
-10 C (14 F): Days with min	60	34	1963	20
-20 C (-4 F): Days with min	10	3	1961	1
20 C (68 F): Tropical nights (min	63	55	2020	43
25 C (77 F): Days with min	3	1	2011	1
10 mm (0.39 in): Days with 10 mm or more rain	72	61	2018	30
25 mm (0.98 in): Days with 25 mm or more rain	72	24	2018	6
50 mm (1.97 in): Days with 50 mm or more rain	63	7	1952	1
100 mm (3.94 in): Days with 100 mm or more rain	11	1	1952	1
10 cm (3.9 in): Days with 10 cm or more snowfall	33	5	1966	2
25 cm (9.8 in): Days with 25 cm or more snowfall	5	1	1958	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1936.

Download the Data

Data for Conowingo 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 2026-10-12. Last revised 12 October 2026 (2026-10-12).

Conowingo Dam Threshold Days by Year (USC00182060)

Key Facts for Conowingo Dam Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

Related