Mahnomen Threshold Days by Year (USC00215012)

18 fixed thresholds counted per year at Mahnomen (USC00215012): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Mahnomen Thresholds

Mahnomen: days with 10 mm (0.39 in) or more of precipitation in 69 years, most in 1949 with 25.
Mahnomen: days with 25 mm (0.98 in) or more of precipitation in 67 years, most in 1998 with 11.
Mahnomen: nights with a minimum temperature at or below 0 C (32 F) in 47 years, most in 1931 with 199.
Mahnomen: nights with a minimum temperature at or below -10 C (14 F) in 47 years, most in 1970 with 123.
18 fixed thresholds have at least one qualifying day at Mahnomen.

Days at or above 30 C (86 F)

46 years with a qualifying day

Days per year at Mahnomen with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 43 in 1998.

Days at or above 30 C (86 F) per year at Mahnomen
Year	Days	Decade average
1931	28	28
1960	15	14.4
1962	5	14.4
1963	18	14.4
1964	23	14.4
1965	6	14.4
1966	17	14.4
1967	13	14.4
1968	11	14.4
1969	22	14.4
1970	40	22.2
1971	11	22.2
1972	22	22.2
1973	22	22.2
1974	16	22.2
1975	11	22.2
1976	38	22.2
1977	20	22.2
1978	29	22.2
1979	13	22.2
1980	37	25.6
1981	16	25.6
1982	18	25.6
1983	34	25.6
1984	25	25.6
1985	4	25.6
1986	20	25.6
1987	26	25.6
1988	42	25.6
1989	34	25.6
1990	29	21.4
1991	30	21.4
1992	9	21.4
1993	10	21.4
1994	7	21.4
1995	27	21.4
1996	17	21.4
1997	21	21.4
1998	43	21.4
2010	13	15.3
2011	19	15.3
2017	14	15.3
2020	18	15.5
2022	11	15.5
2025	19	15.5
2026	14	15.5

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

First to last qualifying date each year at Mahnomen
Year	First date	Last date
1931	1931-05-15	1931-09-11
1960	1960-07-20	1960-09-05
1962	1962-08-05	1962-08-27
1963	1963-06-29	1963-10-05
1964	1964-05-21	1964-09-02
1965	1965-07-22	1965-08-14
1966	1966-06-19	1966-08-31
1967	1967-07-10	1967-08-25
1968	1968-06-03	1968-08-23
1969	1969-05-27	1969-09-12
1970	1970-06-04	1970-09-20
1971	1971-06-27	1971-09-03
1972	1972-05-17	1972-08-30
1973	1973-06-01	1973-08-31
1974	1974-06-28	1974-09-27
1975	1975-07-15	1975-08-25
1976	1976-06-07	1976-09-30
1977	1977-05-13	1977-07-23
1978	1978-05-25	1978-09-09
1979	1979-06-14	1979-09-16
1980	1980-04-20	1980-09-08
1981	1981-07-05	1981-09-12
1982	1982-07-04	1982-09-10
1983	1983-06-25	1983-09-08
1984	1984-05-31	1984-09-20
1985	1985-05-03	1985-07-08
1986	1986-05-27	1986-08-19
1987	1987-04-18	1987-08-03
1988	1988-05-29	1988-08-17
1989	1989-05-12	1989-09-30
1990	1990-04-24	1990-09-25
1991	1991-05-12	1991-09-02
1992	1992-05-07	1992-10-01
1993	1993-05-13	1993-10-06
1994	1994-05-19	1994-09-09
1995	1995-05-31	1995-09-05
1996	1996-06-10	1996-09-06
1997	1997-06-01	1997-08-30
1998	1998-06-26	1998-09-19
2010	2010-05-29	2010-08-30
2011	2011-06-06	2011-10-05
2017	2017-06-02	2017-09-12
2020	2020-06-08	2020-08-24
2022	2022-06-18	2022-09-01
2025	2025-05-11	2025-10-03
2026	2026-04-22	2026-08-17

Every Fixed Threshold

Fixed thresholds at Mahnomen
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	46	43	1998	14
35 C (95 F): Days	19	10	1931	1
90 F (32.2 C): Days	45	29	1988	6
100 F (37.8 C): Days	3	3	1976	3
0 C (32 F): Ice days (max	46	123	1978	52
0 C (32 F): Frost days (min	47	199	1931	118
-10 C (14 F): Days with min	47	123	1970	56
-20 C (-4 F): Days with min	47	79	1978	31
-30 C (-22 F): Days with min	47	25	1979	3
-40 C (-40 F): Days with min	6	3	1996	1
20 C (68 F): Tropical nights (min	40	15	1996	4
25 C (77 F): Days with min	2	1	1977	1
10 mm (0.39 in): Days with 10 mm or more rain	69	25	1949	8
25 mm (0.98 in): Days with 25 mm or more rain	67	11	1998	1
50 mm (1.97 in): Days with 50 mm or more rain	31	3	1941	1
100 mm (3.94 in): Days with 100 mm or more rain	5	1	1949	1
10 cm (3.9 in): Days with 10 cm or more snowfall	44	8	1995	2
25 cm (9.8 in): Days with 25 cm or more snowfall	2	2	1939	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1931.

Download the Data

Data for Mahnomen 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).

Mahnomen Threshold Days by Year (USC00215012)

Key Facts for Mahnomen Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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