Sioux City, IA: September

30 September 2026: September 2026 averaged 68.9°F in Sioux City, IA, the warmest September since 2019, tied 10th warmest of 138 (with 1936).

September 2026

Mean temperature: 68.9°F; Warmest since 2019; 10th warmest of 138
Precipitation: 3.49 in; Wettest since 2023; 40th wettest of 138

A normal September in Sioux City, IA (1991 to 2020): a mean temperature of 64.2°F, between 60.2°F and 68.5°F in eight years of ten and 2.80 in of precipitation, between 0.52 in and 4.68 in in eight years of ten.

The mean temperature of every September in Sioux City, IA since 1889: 68.9°F in 2026; the highest is 71.9°F, in 1931.

Normal range, 60.2 to 68.5°F

Every year, ranked, as a table

Every September in Sioux City, IA from 1889 to 2026, ranked: the mean temperature, the mean high and the mean low from the warmest, the precipitation from the wettest; a year missing more than a tenth of its days is not ranked.

Year	Mean, °F	Rank	High, °F	Rank	Low, °F	Rank	Precipitation, in	Rank
2026	68.9	10	76.5	63	61.3	2	3.49	40
2025	66.4	36	79.7	25	53.2	55	2.05	80
2024	67.7	22	83.3	6	52.1	72	0.22	137
2023	68.8	12	82.4	7	55.2	28	4.49	25
2022	66.8	30	82	9	51.6	81	0.76	120
2021	66.9	28	80.3	17	53.4	52	2.54	66
2020	63	89	75.8	71	50.2	103	1.60	95
2019	69.4	7	80.3	17	58.5	4	4.02	31
2018	65.3	52	75.5	78	55.2	28	7.42	7
2017	66.6	33	78.8	35	54.3	40	2.18	75
2016	67.8	20	79	34	56.6	14	2.78	60
2015	68.3	16	79.1	32	57.5	8	3.13	51
2014	64.3	68	75.8	71	52.8	65	2.79	59
2013	68.4	14	81.2	12	55.6	24	1.44	98
2012	63.2	84	81.7	11	44.6	138	0.47	130
2011	60.2	124	74.4	89	45.9	135	0.31	133
2010	64	75	76.8	59	51.1	92	2.99	55
2009	64.2	70	76.4	65	52.1	72	4.56	23
2008	63.7	80	76.3	66	51	94	3.34	46
2007	63.8	79	77	57	50.6	100	3.67	35
2006	59.6	130	70.9	125	48.4	124	5.45	16
2005	70.1	4	84.9	2	55.2	28	2.84	57
2004	68.4	14	82	9	54.8	32	3.42	43
2003	60.1	126	75	81	45.2	137	6.65	11
2002	64.9	59	78	48	51.8	77	1.27	103
2001	61.3	112	73.4	103	49.2	116	3.39	45
2000	64.4	67	80.3	17	48.5	122	1.06	111
1999	61	114	75	81	47	131	0.52	126
1998	70	5	84.2	3	55.9	21	0.42	131
1997	64.8	61	78.6	40	51	94	2.43	70
1996	60.6	120	71.3	121	49.9	105	2.65	61
1995	60.6	120	73.7	99	47.6	128	3.50	39
1994	66.7	32	78.6	40	54.7	34	4.59	21
1993	58.4	137	70.1	131	46.6	132	1.29	101
1992	62.1	102	74.2	92	49.9	105	2.82	58
1991	64.2	70	76.9	58	51.6	81	2.17	76
1990	67.8	20	80.9	14	54.7	34	0.86	118
1989	61.9	105	74.1	96	49.6	109	4.33	27
1988	64.9	59	76.8	59	53	60	5.17	17
1987	63.9	77	76.3	66	51.6	81	1.44	98
1986	64	75	73.4	103	54.5	38	5.06	19
1985	61.4	111	69.3	136	53.5	49	4.50	24
1984	60.4	122	72.3	118	48.4	124	0.71	122
1983	66.3	38	78.8	35	53.7	47	3.07	52
1982	63.1	85	73.1	108	53.1	58	3.64	36
1981	65.1	57	78.7	37	51.4	87	0.97	113
1980	64.3	68	77.6	51	50.9	97	1.40	100
1979	65.2	54	77.6	51	52.8	65	2.02	82
1978	68	19	80.2	20	55.7	23	1.77	88
1977	64.8	61	75.6	74	54	43	4.90	20
1976	64.2	70	77.6	51	50.8	98	1.96	85
1975	59.6	130	71.5	120	47.6	128	1.17	106
1974	60.2	124	74.2	92	46.1	134	0.87	117
1973	63.1	85	72.8	113	53.4	52	4.04	30
1972	64.1	73	75.3	80	52.9	62	2.62	64
1971	65	58	78.6	40	51.4	87	0.60	123
1970	63.9	77	74.7	85	53.1	58	7.54	5
1969	64.8	61	76.1	69	53.5	49	1.23	105
1968	63	89	74.2	92	51.7	79	4.12	29
1967	62.5	98	74.9	83	50	104	1.08	110
1966	62.3	99	72.9	111	51.6	81	1.29	101
1965	56.9	138	65.1	138	48.7	121	9.69	1
1964	63	89	73	110	53	60	3.03	54
1963	67.1	26	77.1	56	57	13	2.02	82
1962	60.9	116	72.6	116	49.2	116	2.47	68
1961	61.2	113	71.3	121	51	94	2.94	56
1960	65.6	49	77.6	51	53.5	49	1.87	87
1959	63.3	82	74.4	89	52.2	71	1.47	97
1958	65.8	43	78.7	37	52.9	62	0.58	124
1957	61.5	110	72.4	117	50.7	99	5.09	18
1956	64.6	65	79.6	27	49.5	111	0.40	132
1955	66.9	28	79.4	28	54.5	38	1.24	104
1954	66.8	30	78.7	37	54.8	32	1.65	92
1953	64.5	66	80	23	48.9	119	1.12	108
1952	65.7	45	80.4	16	51.1	92	1.51	96
1951	58.9	134	69.9	133	47.9	127	3.61	37
1950	63.1	85	76.3	66	49.8	107	0.07	138
1949	59.7	128	73.6	101	45.9	135	5.99	13
1948	69.2	8	83.5	5	54.9	31	0.31	133
1947	66.3	38	79.3	31	53.2	55	2.25	74
1946	62.8	94	74.3	91	51.2	90	4.25	28
1945	61.6	108	74.2	92	49	118	2.65	61
1944	62.9	93	74.1	96	51.7	79	1.76	89
1943	60.9	116	73.3	105	48.5	122	2.50	67
1942	59.7	128	70.1	131	49.3	112	4.01	32
1941	65.2	54	76.5	63	53.9	44	7.49	6
1940	67.4	25	80.1	21	54.6	36	1.63	93
1939	70.3	3	84.2	3	56.3	17	0.31	133
1938	68.3	16	80.1	21	56.5	15	7.94	4
1937	66.5	35	78.5	43	54.6	36	2.63	63
1936	68.9	10	79.9	24	57.9	6	2.07	79
1935	66	41	77.8	49	54.2	42	1.61	94
1934	59.4	133	70.4	130	48.3	126	3.43	42
1933	69.8	6	80.8	15	58.7	3	5.83	14
1932	63.1	85	74.5	87	51.6	81	2.30	72
1931	71.9	1	82.2	8	61.5	1	3.34	46
1930	65.8	43	77.3	55	54.3	40	2.46	69
1929	60.7	119	69.8	134	51.5	86	3.18	49
1928	61.6	108	73.3	105	49.8	107	2.14	77
1927	66.4	36	75.6	74	57.1	11	3.33	48
1926	61.7	107	70.5	128	52.8	65	7.41	8
1925	68.8	12	79.1	32	58.5	4	2.30	72
1924	59.5	132	69.6	135	49.3	112	1.71	90
1923	65.3	52	74.6	86	56	20	7.36	9
1922	68.1	18	79.7	25	56.5	15	0.49	129
1921	66.3	38	76.6	62	56.1	18	4.59	21
1920	66.6	33	77.8	49	55.3	26	1.94	86
1919	67.1	26	76.7	61	57.6	7	2.56	65
1918	58.9	134	70.8	127	47.1	130	0.52	126
1917	63.4	81	73.1	108	53.6	48	0.97	113
1916	62.2	101	73.2	107	51.2	90	3.41	44
1915	62	104	71.3	121	52.7	68	3.48	41
1914	64.1	73	74.9	83	53.3	54	7.05	10
1913	64.7	64	75.4	79	53.9	44	1.13	107
1912	60.3	123	69.2	137	51.4	87	3.57	38
1911	65.6	49	75.8	71	55.4	25	3.14	50
1910	62.7	95	72.9	111	52.4	69	3.93	33
1909	63	89	72.8	113	53.2	55	1.99	84
1908	69.1	9	81.1	13	57.2	10	1.02	112
1907	62.1	102	73.5	102	50.6	100	2.03	81
1906	65.5	51	75.6	74	55.3	26	8.06	2
1905	65.7	45	75.6	74	55.8	22	6.37	12
1904	63.3	82	74.5	87	52.1	72	0.86	118
1903	60.8	118	71.3	121	50.3	102	3.06	53
1902	59.9	127	70.9	125	48.9	119	4.49	25
1901	62.3	99	72.3	118	52.3	70	7.99	3
1900	62.7	95	73.7	99	51.8	77	5.64	15
1899	62.7	95	76	70	49.3	112	0.26	136
1898	65.2	54	78.4	45	51.9	76	0.95	115
1897	71.8	2	86.1	1	57.5	8	0.51	128
1896	58.5	136	70.5	128	46.5	133	2.09	78
1895	67.7	22	79.4	28	56.1	18	3.91	34
1894	65.7	45	78.5	43	52.9	62	0.73	121
1893	65.7	45	79.4	28	52	75	1.11	109
1892	66	41	78.1	47	53.9	44	0.57	125
1891	67.7	22	78.4	45	57.1	11	0.91	116
1890	61.8	106	74	98	49.6	109	2.36	71
1889	61	114	72.7	115	49.3	112	1.71	90

Warmest, coldest, wettest and driest

Warmest
Year	Mean, °F
1931	71.9
1897	71.8
1939	70.3
2005	70.1
1998	70
1933	69.8
2019	69.4
1948	69.2
1908	69.1
2026	68.9
More years share the last value

Coldest
Year	Mean, °F
1965	56.9
1993	58.4
1896	58.5
1951	58.9
1918	58.9
1934	59.4
1924	59.5
2006	59.6
1975	59.6
1949	59.7
More years share the last value

Wettest
Year	Precipitation, in
1965	9.69
1906	8.06
1901	7.99
1938	7.94
1970	7.54
1941	7.49
2018	7.42
1926	7.41
1923	7.36
1914	7.05

Driest
Year	Precipitation, in
1950	0.07
2024	0.22
1899	0.26
2011	0.31
1948	0.31
1939	0.31
1956	0.40
1998	0.42
2012	0.47
1922	0.49

The hottest, coldest and wettest days

Hottest day: 96°F; 18 September 2026
Coldest night: 50°F; 10 September 2026
Wettest day: 0.61 in; 24 September 2026

Every month, season and year

Months

Seasons

Years

Sioux City, IA the day's answers

All-time records

Every answer in words

September 2026 brought 3.49 in of precipitation in Sioux City, IA, the wettest September since 2023, 40th wettest of 138.
The hottest day of September 2026 in Sioux City, IA: 96°F on Friday 18 September 2026.
The coldest night of September 2026 in Sioux City, IA: a low of 50°F on Thursday 10 September 2026.
The wettest day of September 2026 in Sioux City, IA: 0.61 in on Thursday 24 September 2026.