Donora 1 SW Threshold Days by Year (USC00362190)

18 fixed thresholds counted per year at Donora 1 SW (USC00362190): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Donora 1 SW Thresholds

Donora 1 SW: nights with a minimum temperature at or below 0 C (32 F) in 89 years, most in 1961 with 148.
Donora 1 SW: nights with a minimum temperature at or below -10 C (14 F) in 89 years, most in 1977 with 43.
Donora 1 SW: nights with a minimum temperature at or above 20 C (68 F) in 88 years, most in 1935 with 46.
Donora 1 SW: days with 10 mm (0.39 in) or more of precipitation in 87 years, most in 1979 with 51.
18 fixed thresholds have at least one qualifying day at Donora 1 SW.

Days at or above 30 C (86 F)

80 years with a qualifying day

Days per year at Donora 1 SW with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 99 in 1991.

Days at or above 30 C (86 F) per year at Donora 1 SW
Year	Days	Decade average
1927	38	43.3
1928	41	43.3
1929	51	43.3
1930	65	70.1
1931	71	70.1
1932	84	70.1
1933	75	70.1
1934	69	70.1
1935	57	70.1
1936	80	70.1
1937	59	70.1
1938	63	70.1
1939	78	70.1
1940	52	62.5
1941	73	62.5
1948	53	62.5
1949	72	62.5
1950	33	62
1951	51	62
1952	64	62
1953	75	62
1954	66	62
1955	81	62
1956	51	62
1957	74	62
1958	33	62
1959	92	62
1960	51	42.3
1961	48	42.3
1962	59	42.3
1963	28	42.3
1964	50	42.3
1965	62	42.3
1967	26	42.3
1968	38	42.3
1969	19	42.3
1971	35	41.9
1972	29	41.9
1973	45	41.9
1974	28	41.9
1975	45	41.9
1976	41	41.9
1977	55	41.9
1978	58	41.9
1979	41	41.9
1980	42	49.7
1981	27	49.7
1983	70	49.7
1984	43	49.7
1985	40	49.7
1986	50	49.7
1987	64	49.7
1988	61	49.7
1989	50	49.7
1990	52	51.2
1991	99	51.2
1992	42	51.2
1994	46	51.2
1995	52	51.2
1996	35	51.2
1997	32	51.2
1998	44	51.2
1999	59	51.2
2000	24	38.2
2001	40	38.2
2002	65	38.2
2003	24	38.2
2004	22	38.2
2005	66	38.2
2006	37	38.2
2007	55	38.2
2008	32	38.2
2009	17	38.2
2010	58	40.7
2011	42	40.7
2012	56	40.7
2013	26	40.7
2014	14	40.7
2015	42	40.7
2016	47	40.7

For each year, a bar from the first to the last day at Donora 1 SW meeting 30 C (86 F).

First to last qualifying date each year at Donora 1 SW
Year	First date	Last date
1927	1927-05-09	1927-10-06
1928	1928-05-04	1928-10-12
1929	1929-03-25	1929-09-28
1930	1930-04-11	1930-09-26
1931	1931-05-18	1931-10-07
1932	1932-05-07	1932-09-22
1933	1933-04-10	1933-09-27
1934	1934-05-04	1934-09-26
1935	1935-06-02	1935-09-25
1936	1936-05-01	1936-09-27
1937	1937-05-22	1937-10-06
1938	1938-04-27	1938-10-18
1939	1939-05-06	1939-10-10
1940	1940-05-06	1940-09-21
1941	1941-04-13	1941-10-07
1948	1948-05-09	1948-09-18
1949	1949-05-05	1949-10-12
1950	1950-05-05	1950-09-01
1951	1951-05-02	1951-10-05
1952	1952-04-23	1952-10-02
1953	1953-05-05	1953-10-04
1954	1954-04-20	1954-10-14
1955	1955-05-04	1955-10-08
1956	1956-04-29	1956-09-06
1957	1957-04-20	1957-09-20
1958	1958-04-19	1958-09-26
1959	1959-05-05	1959-10-06
1960	1960-04-17	1960-09-09
1961	1961-05-14	1961-09-25
1962	1962-04-26	1962-09-13
1963	1963-05-08	1963-09-12
1964	1964-05-06	1964-09-17
1965	1965-05-02	1965-09-23
1967	1967-05-27	1967-07-27
1968	1968-06-07	1968-08-24
1969	1969-06-01	1969-09-01
1971	1971-05-18	1971-10-01
1972	1972-05-24	1972-09-18
1973	1973-06-13	1973-09-06
1974	1974-05-14	1974-08-27
1975	1975-05-21	1975-08-27
1976	1976-04-17	1976-09-14
1977	1977-04-19	1977-09-05
1978	1978-05-26	1978-09-21
1979	1979-05-08	1979-09-05
1980	1980-05-29	1980-09-21
1981	1981-05-22	1981-08-29
1983	1983-04-28	1983-09-21
1984	1984-05-22	1984-09-22
1985	1985-04-21	1985-09-26
1986	1986-04-27	1986-09-30
1987	1987-04-21	1987-09-11
1988	1988-05-29	1988-09-12
1989	1989-05-18	1989-09-21
1990	1990-04-25	1990-09-11
1991	1991-05-12	1991-09-19
1992	1992-05-12	1992-09-17
1994	1994-05-23	1994-09-16
1995	1995-06-19	1995-09-08
1996	1996-05-11	1996-09-06
1997	1997-06-21	1997-09-03
1998	1998-05-16	1998-09-28
1999	1999-05-13	1999-09-29
2000	2000-05-07	2000-09-11
2001	2001-04-24	2001-09-10
2002	2002-04-17	2002-10-05
2003	2003-06-25	2003-08-30
2004	2004-05-10	2004-09-05
2005	2005-06-06	2005-10-06
2006	2006-05-30	2006-08-30
2007	2007-05-02	2007-10-09
2008	2008-06-06	2008-09-15
2009	2009-04-26	2009-08-21
2010	2010-04-03	2010-09-08
2011	2011-04-28	2011-09-04
2012	2012-05-04	2012-09-07
2013	2013-05-16	2013-10-07
2014	2014-05-14	2014-09-06
2015	2015-05-08	2015-09-20
2016	2016-05-28	2016-09-24

Every Fixed Threshold

Fixed thresholds at Donora 1 SW
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	80	99	1991	47
35 C (95 F): Days	48	19	1988	6
40 C (104 F): Days	4	2	1930	1
90 F (32.2 C): Days	78	57	1955	11
100 F (37.8 C): Days	13	10	1930	1
0 C (32 F): Ice days (max	81	47	2010	15
0 C (32 F): Frost days (min	89	148	1961	42
-10 C (14 F): Days with min	89	43	1977	17
-20 C (-4 F): Days with min	30	8	1977	1
20 C (68 F): Tropical nights (min	88	46	1935	25
25 C (77 F): Days with min	8	3	1933	1
10 mm (0.39 in): Days with 10 mm or more rain	87	51	1979	4
25 mm (0.98 in): Days with 25 mm or more rain	86	13	1996	8
50 mm (1.97 in): Days with 50 mm or more rain	48	3	1936	1
100 mm (3.94 in): Days with 100 mm or more rain	1	1	2004	1
10 cm (3.9 in): Days with 10 cm or more snowfall	49	5	1936	1
25 cm (9.8 in): Days with 25 cm or more snowfall	10	2	2016	2
50 cm (19.7 in): Days with 50 cm or more snowfall	1	0	n/a	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1927.

Download the Data

Data for Donora 1 SW 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).

Donora 1 SW Threshold Days by Year (USC00362190)

Key Facts for Donora 1 SW Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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