Norris Threshold Days by Year (USC00406619)

16 fixed thresholds counted per year at Norris (USC00406619): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Norris Thresholds

Norris: days with a maximum temperature at or above 30 C (86 F) in 73 years, most in 1936 with 112.
Norris: days with 10 mm (0.39 in) or more of precipitation in 73 years, most in 2009 with 61.
Norris: days with 25 mm (0.98 in) or more of precipitation in 73 years, most in 1994 with 27.
Norris: days with a maximum temperature at or above 90 F (32.2 C) in 72 years, most in 1936 with 80.
16 fixed thresholds have at least one qualifying day at Norris.

Days at or above 30 C (86 F)

73 years with a qualifying day

Days per year at Norris with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 112 in 1936.

Days at or above 30 C (86 F) per year at Norris
Year	Days	Decade average
1935	82	80
1936	112	80
1937	71	80
1938	52	80
1939	83	80
1940	63	68.5
1946	74	68.5
1954	100	79.5
1955	76	79.5
1956	79	79.5
1957	104	79.5
1958	50	79.5
1959	68	79.5
1960	71	69.7
1961	54	69.7
1962	84	69.7
1963	53	69.7
1964	88	69.7
1965	72	69.7
1966	69	69.7
1967	35	69.7
1968	81	69.7
1969	90	69.7
1970	100	77.1
1971	75	77.1
1972	69	77.1
1973	85	77.1
1974	61	77.1
1975	94	77.1
1976	60	77.1
1977	83	77.1
1978	67	77.1
1985	53	64
1986	80	64
1987	77	64
1988	74	64
1989	36	64
1990	60	52.7
1991	51	52.7
1992	17	52.7
1993	70	52.7
1994	32	52.7
1995	59	52.7
1996	39	52.7
1997	52	52.7
1998	89	52.7
1999	58	52.7
2000	62	63.8
2001	48	63.8
2002	95	63.8
2004	53	63.8
2005	66	63.8
2006	57	63.8
2007	102	63.8
2008	65	63.8
2009	26	63.8
2010	83	65
2011	80	65
2012	69	65
2013	25	65
2014	45	65
2015	65	65
2016	100	65
2017	38	65
2018	70	65
2019	75	65
2020	39	43.3
2021	41	43.3
2022	36	43.3
2023	24	43.3
2024	47	43.3
2025	53	43.3
2026	63	43.3

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

First to last qualifying date each year at Norris
Year	First date	Last date
1935	1935-04-26	1935-10-14
1936	1936-04-16	1936-09-29
1937	1937-04-19	1937-09-09
1938	1938-06-17	1938-09-13
1939	1939-05-24	1939-10-09
1940	1940-04-02	1940-09-23
1946	1946-04-02	1946-10-05
1954	1954-04-27	1954-10-15
1955	1955-04-18	1955-09-24
1956	1956-04-28	1956-09-17
1957	1957-04-21	1957-09-13
1958	1958-05-26	1958-09-27
1959	1959-04-09	1959-10-06
1960	1960-04-24	1960-09-23
1961	1961-06-01	1961-09-26
1962	1962-05-01	1962-09-14
1963	1963-04-02	1963-10-22
1964	1964-05-18	1964-09-20
1965	1965-04-23	1965-09-22
1966	1966-05-09	1966-09-04
1967	1967-04-05	1967-09-20
1968	1968-05-24	1968-10-03
1969	1969-05-04	1969-09-18
1970	1970-04-19	1970-09-26
1971	1971-04-19	1971-10-04
1972	1972-05-25	1972-09-26
1973	1973-06-03	1973-09-27
1974	1974-05-20	1974-09-30
1975	1975-05-19	1975-10-12
1976	1976-04-19	1976-09-13
1977	1977-04-12	1977-09-08
1978	1978-04-09	1978-09-24
1985	1985-04-19	1985-11-19
1986	1986-04-26	1986-10-05
1987	1987-04-21	1987-09-11
1988	1988-04-06	1988-09-24
1989	1989-04-26	1989-09-22
1990	1990-04-25	1990-09-11
1991	1991-04-18	1991-09-19
1992	1992-06-08	1992-09-10
1993	1993-05-08	1993-09-15
1994	1994-04-27	1994-08-19
1995	1995-04-11	1995-09-13
1996	1996-05-10	1996-09-12
1997	1997-05-19	1997-09-21
1998	1998-05-15	1998-10-01
1999	1999-05-12	1999-09-13
2000	2000-05-07	2000-09-20
2001	2001-04-09	2001-09-07
2002	2002-04-17	2002-10-04
2004	2004-05-08	2004-09-07
2005	2005-05-12	2005-09-26
2006	2006-04-15	2006-08-30
2007	2007-03-26	2007-10-09
2008	2008-06-05	2008-09-14
2009	2009-04-25	2009-08-16
2010	2010-04-03	2010-09-25
2011	2011-04-10	2011-09-05
2012	2012-03-21	2012-09-08
2013	2013-04-11	2013-09-13
2014	2014-05-05	2014-09-07
2015	2015-05-07	2015-09-09
2016	2016-04-19	2016-10-21
2017	2017-04-15	2017-09-28
2018	2018-05-04	2018-09-23
2019	2019-05-19	2019-10-06
2020	2020-06-04	2020-09-12
2021	2021-05-22	2021-08-30
2022	2022-05-21	2022-09-03
2023	2023-04-05	2023-09-05
2024	2024-06-15	2024-09-23
2025	2025-04-05	2025-08-23
2026	2026-04-15	2026-09-23

Every Fixed Threshold

Fixed thresholds at Norris
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	73	112	1936	63
35 C (95 F): Days	33	29	1936	5
40 C (104 F): Days	2	2	1964	2
90 F (32.2 C): Days	72	80	1936	11
100 F (37.8 C): Days	9	8	1936	3
0 C (32 F): Ice days (max	68	23	2010	7
0 C (32 F): Frost days (min	72	124	1969	76
-10 C (14 F): Days with min	67	33	1963	13
-20 C (-4 F): Days with min	12	4	1940	2
20 C (68 F): Tropical nights (min	71	36	2010	21
25 C (77 F): Days with min	1	1	1936	1
10 mm (0.39 in): Days with 10 mm or more rain	73	61	2009	36
25 mm (0.98 in): Days with 25 mm or more rain	73	27	1994	15
50 mm (1.97 in): Days with 50 mm or more rain	68	8	1967	3
100 mm (3.94 in): Days with 100 mm or more rain	19	3	1973	1
10 cm (3.9 in): Days with 10 cm or more snowfall	16	2	1967	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1935.

Download the Data

Data for Norris 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).

Norris Threshold Days by Year (USC00406619)

Key Facts for Norris Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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