Ottumwa Threshold Days by Year

20 fixed thresholds counted per year at Ottumwa (USC00396397): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Ottumwa Thresholds

Ottumwa: days with 10 mm (0.39 in) or more of precipitation in 27 years, most in 1915 with 26.
Ottumwa: days with 25 mm (0.98 in) or more of precipitation in 26 years, most in 1915 with 8.
Ottumwa: days with a maximum temperature at or above 30 C (86 F) in 25 years, most in 1936 with 100.
Ottumwa: days with a maximum temperature at or above 35 C (95 F) in 25 years, most in 1936 with 57.
20 fixed thresholds have at least one qualifying day at Ottumwa.

Days at or above 30 C (86 F)

25 years with a qualifying day

Days per year at Ottumwa with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 100 in 1936.

Days at or above 30 C (86 F) per year at Ottumwa
Year	Days	Decade average
1909	63	63
1912	42	41.8
1914	69	41.8
1915	9	41.8
1917	47	41.8
1924	47	57.8
1925	66	57.8
1926	60	57.8
1927	41	57.8
1929	75	57.8
1930	68	79.4
1931	82	79.4
1932	57	79.4
1933	83	79.4
1934	98	79.4
1935	72	79.4
1936	100	79.4
1937	74	79.4
1938	68	79.4
1939	92	79.4
1940	83	58.8
1941	67	58.8
1942	35	58.8
1943	68	58.8
1944	41	58.8

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

First to last qualifying date each year at Ottumwa
Year	First date	Last date
1909	1909-05-04	1909-10-06
1912	1912-05-09	1912-10-04
1914	1914-05-18	1914-10-02
1915	1915-04-16	1915-09-02
1917	1917-05-16	1917-09-23
1924	1924-04-14	1924-09-30
1925	1925-05-19	1925-09-25
1926	1926-04-29	1926-10-10
1927	1927-05-01	1927-10-24
1929	1929-05-22	1929-10-16
1930	1930-04-08	1930-09-22
1931	1931-05-14	1931-09-29
1932	1932-05-13	1932-10-16
1933	1933-05-22	1933-10-29
1934	1934-04-28	1934-10-15
1935	1935-06-13	1935-10-15
1936	1936-04-19	1936-10-08
1937	1937-05-27	1937-10-03
1938	1938-04-30	1938-10-03
1939	1939-04-30	1939-10-01
1940	1940-05-11	1940-09-22
1941	1941-05-12	1941-09-19
1942	1942-04-14	1942-10-11
1943	1943-03-29	1943-10-11
1944	1944-05-13	1944-09-25

Every Fixed Threshold

Fixed thresholds at Ottumwa
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	25	100	1936	41
35 C (95 F): Days	25	57	1936	12
40 C (104 F): Days	21	32	1936	2
45 C (113 F): Days	4	3	1936	3
90 F (32.2 C): Days	25	84	1936	26
100 F (37.8 C): Days	23	44	1936	5
110 F (43.3 C): Days	10	9	1936	1
0 C (32 F): Ice days (max	25	75	1936	63
0 C (32 F): Frost days (min	23	195	1909	190
-10 C (14 F): Days with min	23	92	1936	87
-20 C (-4 F): Days with min	23	43	1936	19
-30 C (-22 F): Days with min	20	17	1936	3
-40 C (-40 F): Days with min	2	2	1912	1
20 C (68 F): Tropical nights (min	22	26	1936	4
25 C (77 F): Days with min	8	7	1936	1
10 mm (0.39 in): Days with 10 mm or more rain	27	26	1915	11
25 mm (0.98 in): Days with 25 mm or more rain	26	8	1915	4
50 mm (1.97 in): Days with 50 mm or more rain	6	2	1915	2
10 cm (3.9 in): Days with 10 cm or more snowfall	5	4	1935	2
25 cm (9.8 in): Days with 25 cm or more snowfall	1	1	1944	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1909.

Download the Data

Data for Ottumwa 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 2026-10-16 (16 October 2026). Threshold counts are computed by this site.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).

Ottumwa Threshold Days by Year

Key Facts for Ottumwa Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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