Helena 1 SSE Threshold Days by Year

20 fixed thresholds counted per year at Helena 1 SSE (USC00344019): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Helena 1 SSE Thresholds

Helena 1 SSE: days with 10 mm (0.39 in) or more of precipitation in 83 years, most in 1957 with 33.
Helena 1 SSE: days with 25 mm (0.98 in) or more of precipitation in 83 years, most in 1999 with 17.
Helena 1 SSE: days with a maximum temperature at or above 30 C (86 F) in 67 years, most in 1911 with 136.
Helena 1 SSE: days with a maximum temperature at or above 35 C (95 F) in 67 years, most in 2011 with 85.
20 fixed thresholds have at least one qualifying day at Helena 1 SSE.

Days at or above 30 C (86 F)

67 years with a qualifying day

Days per year at Helena 1 SSE with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 136 in 1911.

Days at or above 30 C (86 F) per year at Helena 1 SSE
Year	Days	Decade average
1910	121	128.5
1911	136	128.5
1962	116	99.9
1963	124	99.9
1964	98	99.9
1965	98	99.9
1966	97	99.9
1967	81	99.9
1968	92	99.9
1969	93	99.9
1970	108	103.3
1971	108	103.3
1972	107	103.3
1973	102	103.3
1974	84	103.3
1975	105	103.3
1976	97	103.3
1977	107	103.3
1978	113	103.3
1979	102	103.3
1980	125	104.1
1981	108	104.1
1982	99	104.1
1983	99	104.1
1984	119	104.1
1985	97	104.1
1986	102	104.1
1987	100	104.1
1988	104	104.1
1989	88	104.1
1990	103	103.2
1991	115	103.2
1992	78	103.2
1993	92	103.2
1994	123	103.2
1995	95	103.2
1996	105	103.2
1997	102	103.2
1998	127	103.2
1999	92	103.2
2000	111	104.1
2001	111	104.1
2002	102	104.1
2003	98	104.1
2004	96	104.1
2005	121	104.1
2006	127	104.1
2007	95	104.1
2008	95	104.1
2009	85	104.1
2010	117	114
2011	124	114
2012	125	114
2013	102	114
2014	115	114
2015	102	114
2016	111	114
2017	112	114
2018	126	114
2019	106	114
2020	107	120.1
2021	115	120.1
2022	131	120.1
2023	114	120.1
2024	127	120.1
2025	106	120.1
2026	141	120.1

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

First to last qualifying date each year at Helena 1 SSE
Year	First date	Last date
1910	1910-03-05	1910-10-26
1911	1911-02-01	1911-10-14
1962	1962-02-12	1962-10-15
1963	1963-03-29	1963-10-16
1964	1964-05-04	1964-10-17
1965	1965-04-22	1965-10-11
1966	1966-04-01	1966-10-28
1967	1967-03-11	1967-10-05
1968	1968-05-02	1968-10-31
1969	1969-05-22	1969-10-10
1970	1970-04-28	1970-10-07
1971	1971-03-28	1971-10-13
1972	1972-04-07	1972-10-12
1973	1973-05-19	1973-10-24
1974	1974-04-01	1974-09-12
1975	1975-05-19	1975-10-22
1976	1976-03-26	1976-10-12
1977	1977-04-29	1977-10-27
1978	1978-05-12	1978-10-22
1979	1979-05-20	1979-10-22
1980	1980-04-21	1980-11-09
1981	1981-04-13	1981-10-05
1982	1982-04-13	1982-10-19
1983	1983-05-07	1983-10-06
1984	1984-05-11	1984-10-07
1985	1985-05-16	1985-09-20
1986	1986-04-25	1986-09-29
1987	1987-04-18	1987-09-26
1988	1988-05-13	1988-10-18
1989	1989-03-12	1989-10-15
1990	1990-05-15	1990-10-07
1991	1991-03-06	1991-10-24
1992	1992-05-01	1992-10-14
1993	1993-05-31	1993-10-07
1994	1994-03-18	1994-10-03
1995	1995-03-23	1995-10-23
1996	1996-02-23	1996-09-24
1997	1997-05-18	1997-10-07
1998	1998-04-26	1998-10-15
1999	1999-05-09	1999-10-16
2000	2000-04-06	2000-10-04
2001	2001-04-27	2001-10-05
2002	2002-04-18	2002-10-02
2003	2003-05-05	2003-10-24
2004	2004-05-05	2004-10-22
2005	2005-04-21	2005-10-19
2006	2006-04-14	2006-11-09
2007	2007-06-06	2007-10-15
2008	2008-05-02	2008-09-29
2009	2009-03-06	2009-10-01
2010	2010-04-01	2010-10-17
2011	2011-04-04	2011-10-05
2012	2012-04-25	2012-11-03
2013	2013-04-30	2013-10-05
2014	2014-04-13	2014-10-27
2015	2015-04-07	2015-10-16
2016	2016-04-11	2016-10-29
2017	2017-02-12	2017-10-15
2018	2018-04-12	2018-10-06
2019	2019-05-16	2019-10-03
2020	2020-04-08	2020-10-22
2021	2021-05-09	2021-10-24
2022	2022-04-10	2022-10-23
2023	2023-04-04	2023-10-23
2024	2024-02-27	2024-10-29
2025	2025-04-14	2025-10-18
2026	2026-03-20	2026-10-12

Every Fixed Threshold

Fixed thresholds at Helena 1 SSE
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	67	136	1911	141
35 C (95 F): Days	67	85	2011	81
40 C (104 F): Days	51	42	2011	21
45 C (113 F): Days	2	1	1911	1
90 F (32.2 C): Days	67	115	1911	111
100 F (37.8 C): Days	67	67	2011	51
110 F (43.3 C): Days	11	3	1986	1
0 C (32 F): Ice days (max	67	34	1978	5
0 C (32 F): Frost days (min	67	133	2013	39
-10 C (14 F): Days with min	67	41	1978	10
-20 C (-4 F): Days with min	16	7	1989	2
20 C (68 F): Tropical nights (min	67	86	1911	96
25 C (77 F): Days with min	43	16	2011	27
10 mm (0.39 in): Days with 10 mm or more rain	83	33	1957	18
25 mm (0.98 in): Days with 25 mm or more rain	83	17	1999	6
50 mm (1.97 in): Days with 50 mm or more rain	62	7	1960	3
100 mm (3.94 in): Days with 100 mm or more rain	14	2	1960	1
200 mm (7.87 in): Days with 200 mm or more rain	1	1	2008	1
10 cm (3.9 in): Days with 10 cm or more snowfall	43	6	1987	2
25 cm (9.8 in): Days with 25 cm or more snowfall	6	1	1971	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1910.

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Data for Helena 1 SSE 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 2026-10-15 (15 October 2026). Threshold counts are computed by this site.

Data as of 2026-10-16. Last revised 16 October 2026 (2026-10-16).

Helena 1 SSE Threshold Days by Year

Key Facts for Helena 1 SSE Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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