Dearborn Threshold Days by Year

17 fixed thresholds counted per year at Dearborn (USC00202015): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Dearborn Thresholds

Dearborn: days with 10 mm (0.39 in) or more of precipitation in 69 years, most in 2011 with 41.
Dearborn: days with 25 mm (0.98 in) or more of precipitation in 69 years, most in 1997 with 12.
Dearborn: days with a maximum temperature at or above 30 C (86 F) in 66 years, most in 2002 with 69.
Dearborn: days with a maximum temperature at or above 90 F (32.2 C) in 66 years, most in 1988 with 42.
17 fixed thresholds have at least one qualifying day at Dearborn.

Days at or above 30 C (86 F)

66 years with a qualifying day

Days per year at Dearborn with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 69 in 2002.

Days at or above 30 C (86 F) per year at Dearborn
Year	Days	Decade average
1953	52	45.6
1954	42	45.6
1955	62	45.6
1956	37	45.6
1957	38	45.6
1958	27	45.6
1959	61	45.6
1960	30	39.8
1961	37	39.8
1962	36	39.8
1963	39	39.8
1966	56	39.8
1967	29	39.8
1968	48	39.8
1969	43	39.8
1970	56	42.1
1971	64	42.1
1972	51	42.1
1973	52	42.1
1974	42	42.1
1975	35	42.1
1976	23	42.1
1977	33	42.1
1978	38	42.1
1979	27	42.1
1980	34	32.4
1981	16	32.4
1982	25	32.4
1983	39	32.4
1984	34	32.4
1985	20	32.4
1986	30	32.4
1987	48	32.4
1988	56	32.4
1989	22	32.4
1990	29	39.4
1991	61	39.4
1992	7	39.4
1993	39	39.4
1994	29	39.4
1995	48	39.4
1997	26	39.4
1998	60	39.4
1999	56	39.4
2000	28	39.1
2001	47	39.1
2002	69	39.1
2003	31	39.1
2004	30	39.1
2005	44	39.1
2007	56	39.1
2008	37	39.1
2009	10	39.1
2011	35	30.8
2012	50	30.8
2013	17	30.8
2014	16	30.8
2015	21	30.8
2016	39	30.8
2017	32	30.8
2018	36	30.8
2019	31	30.8
2022	37	31.8
2023	18	31.8
2025	36	31.8
2026	36	31.8

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

First to last qualifying date each year at Dearborn
Year	First date	Last date
1953	1953-05-30	1953-10-03
1954	1954-06-09	1954-09-08
1955	1955-05-03	1955-09-20
1956	1956-05-22	1956-09-05
1957	1957-06-15	1957-09-02
1958	1958-06-30	1958-09-04
1959	1959-05-06	1959-09-29
1960	1960-06-04	1960-09-09
1961	1961-06-10	1961-09-14
1962	1962-05-14	1962-09-14
1963	1963-05-08	1963-10-07
1966	1966-05-27	1966-09-03
1967	1967-06-08	1967-10-05
1968	1968-05-15	1968-09-24
1969	1969-05-28	1969-09-07
1970	1970-05-19	1970-09-22
1971	1971-05-18	1971-10-03
1972	1972-05-21	1972-09-18
1973	1973-06-05	1973-09-28
1974	1974-06-04	1974-08-27
1975	1975-05-20	1975-08-26
1976	1976-06-08	1976-09-09
1977	1977-05-18	1977-09-02
1978	1978-05-28	1978-09-21
1979	1979-05-09	1979-09-06
1980	1980-04-23	1980-09-23
1981	1981-06-16	1981-09-12
1982	1982-05-19	1982-09-15
1983	1983-06-12	1983-09-19
1984	1984-06-07	1984-09-23
1985	1985-04-20	1985-09-09
1986	1986-05-31	1986-09-30
1987	1987-04-22	1987-08-18
1988	1988-05-16	1988-09-19
1989	1989-06-08	1989-09-09
1990	1990-04-25	1990-09-07
1991	1991-05-13	1991-09-17
1992	1992-05-18	1992-08-27
1993	1993-05-11	1993-09-15
1994	1994-04-26	1994-09-24
1995	1995-06-17	1995-09-07
1997	1997-06-12	1997-10-08
1998	1998-05-15	1998-09-28
1999	1999-05-19	1999-09-29
2000	2000-05-07	2000-09-04
2001	2001-06-12	2001-09-09
2002	2002-06-01	2002-10-02
2003	2003-06-23	2003-09-12
2004	2004-05-11	2004-09-13
2005	2005-06-05	2005-10-05
2007	2007-05-16	2007-10-09
2008	2008-05-27	2008-09-04
2009	2009-04-25	2009-08-17
2011	2011-05-31	2011-09-04
2012	2012-03-23	2012-09-05
2013	2013-05-21	2013-09-12
2014	2014-05-09	2014-09-06
2015	2015-05-08	2015-09-09
2016	2016-05-29	2016-09-08
2017	2017-05-18	2017-09-27
2018	2018-05-26	2018-09-19
2019	2019-05-26	2019-10-02
2022	2022-05-13	2022-09-19
2023	2023-05-30	2023-10-04
2025	2025-04-30	2025-10-07
2026	2026-05-18	2026-10-14

Every Fixed Threshold

Fixed thresholds at Dearborn
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	66	69	2002	36
35 C (95 F): Days	40	20	1988	3
40 C (104 F): Days	1	1	1988	1
90 F (32.2 C): Days	66	42	1988	12
100 F (37.8 C): Days	7	8	1988	1
0 C (32 F): Ice days (max	66	69	1978	33
0 C (32 F): Frost days (min	62	159	1978	73
-10 C (14 F): Days with min	62	60	2014	29
-20 C (-4 F): Days with min	41	10	1994	2
20 C (68 F): Tropical nights (min	62	30	1955	30
25 C (77 F): Days with min	10	2	2011	1
10 mm (0.39 in): Days with 10 mm or more rain	69	41	2011	20
25 mm (0.98 in): Days with 25 mm or more rain	69	12	1997	5
50 mm (1.97 in): Days with 50 mm or more rain	29	3	1968	4
100 mm (3.94 in): Days with 100 mm or more rain	4	1	1957	1
10 cm (3.9 in): Days with 10 cm or more snowfall	45	4	1977	1
25 cm (9.8 in): Days with 25 cm or more snowfall	4	1	1974	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1953.

Download the Data

Data for Dearborn 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).

Dearborn Threshold Days by Year

Key Facts for Dearborn Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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