Waterloo, IA: September

30 September 2026: September 2026 averaged 67°F in Waterloo, IA, the warmest September since 2025, tied 17th warmest of 132 (with 1998 and 1927).

September 2026

Mean temperature: 67°F; Warmest since 2025; 17th warmest of 132
Precipitation: 8.06 in; Wettest since 2018; 10th wettest of 132

A normal September in Waterloo, IA (1991 to 2020): a mean temperature of 63.1°F, between 60.3°F and 66.8°F in eight years of ten and 2.59 in of precipitation, between 1.13 in and 5.20 in in eight years of ten.

The mean temperature of every September in Waterloo, IA since 1895: 67°F in 2026; the highest is 70.3°F, in 1931.

Normal range, 60.3 to 66.8°F

Every year, ranked, as a table

Every September in Waterloo, IA from 1895 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	67	17	75	66	58.9	3	8.06	10
2025	67.2	12	80.4	11	54	23	0.89	122
2024	68.3	8	82.9	2	53.7	31	0.44	131
2023	69.5	3	82.9	2	56.1	9	1.90	97
2022	65.3	39	77.4	40	53.2	39	1.13	121
2021	67.1	13	80.5	10	53.7	31	1.31	116
2020	62.1	82	73.4	90	50.9	74	5.17	27
2019	69.5	3	79.6	22	59.4	1	5.05	30
2018	64	52	74.2	82	53.8	29	13.35	1
2017	66	29	79.8	18	52.2	50	0.79	126
2016	66.8	20	77.3	41	56.3	7	7.32	13
2015	68.3	8	79.8	18	56.8	4	2.59	73
2014	61.4	93	73.5	88	49.3	94	1.66	102
2013	65.8	32	78.6	33	52.9	43	1.48	108
2012	61.4	93	76.6	47	46.1	125	1.88	98
2011	59.1	121	70.4	121	47.7	114	2.66	71
2010	62.7	77	74.6	71	50.8	77	2.42	84
2009	63	70	75.1	63	50.8	77	2.09	91
2008	63.6	59	74.9	69	52.3	49	2.59	73
2007	64.5	46	77.3	41	51.8	57	4.18	37
2006	59.6	118	70.7	119	48.5	104	5.44	24
2005	66.3	28	79.6	22	53	41	3.06	62
2004	66.7	22	80.4	11	53	41	0.71	128
2003	61.3	96	75.1	63	47.6	116	1.98	96
2002	65.8	32	79.8	18	51.9	52	1.37	113
2001	60.4	109	72.4	102	48.3	108	3.74	47
2000	64.2	49	77.5	38	51	69	1.59	105
1999	61.4	93	75.8	52	47.1	120	0.87	123
1998	67	17	80.7	9	53.3	38	1.16	120
1997	63.1	66	74.8	70	51.3	63	3.14	57
1996	62.6	78	74.5	75	50.6	84	3.90	44
1995	60.7	102	73.4	90	47.9	112	2.44	81
1994	65.9	31	77.6	37	54.1	20	3.67	49
1993	58.2	125	68.7	129	47.7	114	2.86	67
1992	60.5	108	73.1	94	47.9	112	2.23	88
1991	60.6	106	72.1	104	49.1	96	2.92	65
1990	64.7	43	76.4	48	53.1	40	1.46	109
1989	59.7	117	72.3	103	47	121	3.07	60
1988	64.7	43	78.6	33	50.7	81	1.65	103
1987	62.3	80	74.3	78	50.3	87	1.84	99
1986	63.9	55	73.6	86	54.1	20	4.48	35
1985	63.2	63	72.5	101	53.9	26	5.27	25
1984	60.3	111	73.4	90	47.2	118	1.57	106
1983	63	70	75.2	61	50.7	81	3.19	56
1982	61.5	91	71.4	112	51.7	59	1.44	110
1981	60.7	102	73	97	48.3	108	3.13	58
1980	63.2	63	75.2	61	51.3	63	3.74	47
1979	66	29	78.7	32	53.4	35	0.75	127
1978	67.1	13	79.4	25	54.8	15	7.91	11
1977	60.7	102	70.2	124	51.2	68	6.09	21
1976	60.7	102	75.7	54	45.6	127	1.36	114
1975	57	132	68.4	130	45.7	126	0.80	125
1974	58	128	71.1	115	44.9	130	2.14	90
1973	61.7	86	70.1	128	53.4	35	6.88	14
1972	61.2	97	72	105	50.3	87	4.86	32
1971	63.4	60	75.8	52	51	69	2.56	75
1970	61.8	85	72.6	100	51	69	5.20	26
1969	61.1	98	73.1	94	49	98	1.35	115
1968	60.2	112	71.6	110	48.8	101	3.61	51
1967	58.1	126	71.7	109	44.5	131	1.40	111
1966	61.5	91	73.9	84	49	98	0.55	130
1965	58.6	123	67.8	132	49.4	93	11.38	3
1964	60.9	100	72	105	49.8	91	5.17	27
1963	63.7	57	75.5	56	51.9	52	2.52	77
1962	58.6	123	70.2	124	47	121	1.73	100
1961	61.7	86	71.4	112	51.9	52	8.13	8
1960	64.5	46	75	66	54	23	5.06	29
1959	63.3	61	74.1	83	52.4	46	4.16	39
1958	62.4	79	73.7	85	51	69	3.85	46
1957	59.9	116	70.9	117	48.8	101	1.18	119
1956	60.1	113	73.1	94	47	121	2.46	79
1955	65.1	42	78.9	29	51.3	63	2.42	84
1954	65.5	36	76.3	49	54.8	15	2.92	65
1953	63.7	57	79.2	27	48.2	111	0.42	132
1952	64.7	43	80.2	15	49.2	95	0.61	129
1951	59.6	118	70.2	124	49	98	1.62	104
1950	62.9	72	75.3	59	50.5	86	4.16	39
1949	58	128	70.7	119	45.4	128	4.09	41
1948	66.8	20	79.5	24	54	23	1.19	118
1947	66.7	22	77.5	38	55.9	10	1.54	107
1946	62.1	82	73.3	93	50.9	74	6.23	19
1945	61.6	89	71.8	107	51.3	63	3.38	53
1944	63.9	55	73.5	88	54.3	18	3.07	60
1943	58.9	122	70.2	124	47.6	116	2.84	68
1942	60.1	113	70.3	122	49.9	90	4.88	31
1941	65.6	35	77.3	41	53.9	26	11.63	2
1940	64.4	48	77.2	45	51.7	59	4.07	42
1939	68.7	7	82.3	4	55.1	13	1.25	117
1938	65.7	34	78	36	53.5	34	7.35	12
1937	65.4	37	79.3	26	51.4	62	2.46	79
1936	66.7	22	76.8	46	56.5	5	8.12	9
1935	64.2	49	76.1	50	52.4	46	2.65	72
1934	60.6	106	71.6	110	49.6	92	6.44	18
1933	69	6	81.7	6	56.3	7	2.43	82
1932	61.9	84	75.5	56	48.3	108	2.42	84
1931	70.3	1	81.4	8	59.2	2	9.09	6
1930	65.3	39	79.8	18	50.8	77	2.02	94
1929	62.9	72	74.5	75	51.3	63	3.66	50
1928	60.4	109	73.6	86	47.2	118	3.10	59
1927	67	17	78.8	30	55.3	11	4.80	34
1926	63.2	63	72.9	98	53.6	33	8.33	7
1925	69.1	5	81.6	7	56.5	5	6.13	20
1924	58.1	126	71.1	115	45	129	2.28	87
1923	64	52	75.3	59	52.6	45	6.67	17
1922	66.4	27	80.4	11	52.4	46	2.52	77
1921	67.1	13	80.1	16	54.1	20	6.77	16
1920	67.1	13	79.9	17	54.2	19	1.71	101
1919	66.6	26	79.2	27	53.9	26	6.84	15
1918	57.6	131	70.8	118	44.3	132	2.01	95
1917	60.9	100	72.9	98	48.8	101	4.17	38
1916	61.7	86	74.4	77	49.1	96	3.20	55
1915	63.1	66	74.6	71	51.6	61	9.18	5
1914	63.3	61	76	51	50.6	84	9.76	4
1913	62.9	72	75.1	63	50.7	81	3.90	44
1912	61.1	98	71.3	114	50.9	74	5.75	22
1911	63.1	66	74.3	78	51.8	57	2.43	82
1910	62.8	76	74.6	71	51	69	2.98	64
1909	62.3	80	74.3	78	50.2	89	2.08	92
1908	68	10	82.2	5	53.8	29	1.38	112
1907	63.1	66	74.3	78	51.9	52	3.26	54
1906	67.7	11	80.3	14	55.2	12	2.55	76
1905	65.4	37	77.3	41	53.4	35	2.99	63
1904	64	52	75.7	54	52.2	50	2.15	89
1903	60.1	113	71.8	107	48.4	107	2.75	70
1902	59.4	120	70.3	122	48.5	104	4.86	32
1901	62.9	72	75	66	50.8	77	3.57	52
1900	64.2	49	75.4	58	52.9	43	5.48	23
1899	61.6	89	74.6	71	48.5	104	0.84	124
1898	65.2	41	78.4	35	51.9	52	2.07	93
1897	69.9	2	84.7	1	55.1	13	2.77	69
1896	57.7	130	68.4	130	47	121	4.36	36
1895	66.7	22	78.8	30	54.6	17	4.01	43

Warmest, coldest, wettest and driest

Warmest
Year	Mean, °F
1931	70.3
1897	69.9
2023	69.5
2019	69.5
1925	69.1
1933	69
1939	68.7
2024	68.3
2015	68.3
1908	68

Coldest
Year	Mean, °F
1975	57
1918	57.6
1896	57.7
1974	58
1949	58
1967	58.1
1924	58.1
1993	58.2
1965	58.6
1962	58.6

Wettest
Year	Precipitation, in
2018	13.35
1941	11.63
1965	11.38
1914	9.76
1915	9.18
1931	9.09
1926	8.33
1961	8.13
1936	8.12
2026	8.06

Driest
Year	Precipitation, in
1953	0.42
2024	0.44
1966	0.55
1952	0.61
2004	0.71
1979	0.75
2017	0.79
1975	0.80
1899	0.84
1999	0.87

The hottest, coldest and wettest days

Hottest day: 92°F; 1 September 2026
Coldest night: 45°F; 23 September 2026
Wettest day: 1.07 in; 27 September 2026

Every month, season and year

Months

Seasons

Years

Waterloo, IA the day's answers

All-time records

Every answer in words

September 2026 brought 8.06 in of precipitation in Waterloo, IA, the wettest September since 2018, 10th wettest of 132.
The hottest day of September 2026 in Waterloo, IA: 92°F on Tuesday 1 September 2026.
The coldest night of September 2026 in Waterloo, IA: a low of 45°F on Wednesday 23 September 2026.
The wettest day of September 2026 in Waterloo, IA: 1.07 in on Sunday 27 September 2026.