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Sioux City September Weather

Averages and records for weather in Sioux City, Iowa in the month of September.

Typical Sioux City September Weather 1991–2020
Average daily high	77.2 °F
Average daily low	51.4 °F
Average monthly precipitation	2.8 inches
Average monthly snow	none
Daily chance of precipitation	26.7%
Daily chance of snow	0%

Sioux City September Weather Records 1948–2024
Highest temperature	103 °F	September 2, 2000
Lowest temperature	25 °F	September 23, 2012
Highest daily low	77 °F	September 17, 1955
Lowest daily high	41 °F	September 29, 1985
Hottest average high temperature	84.9 °F	2005
Coldest average high temperature	65.1 °F	1965
Most daily precipitation	3.1 inches	September 3, 2009
Most monthly precipitation	9.7 inches	1965
Most daily snow	0.4 inches	September 30, 1961
Most monthly snow	0.4 inches	1961

Note: Daily averages are a moving average which includes 14 days before and after

Day	Average (°F)		Record (°F)
Day	High	Low	High	Low
September 1	81.2	57.6	98	38
September 2	81.1	57.4	103	42
September 3	80.9	57.1	99	37
September 4	80.7	56.8	98	44
September 5	80.4	56.5	96	40
September 6	80.1	56.1	102	39
September 7	79.7	55.6	101	38
September 8	79.3	55.2	98	35
September 9	79.0	54.6	97	37
September 10	78.6	54.1	96	36
September 11	78.3	53.6	98	36
September 12	78.0	53.1	93	38
September 13	77.7	52.6	96	34
September 14	77.4	52.1	91	35
September 15	77.2	51.6	98	32
September 16	77.0	51.2	97	37
September 17	76.7	50.7	96	33
September 18	76.3	50.3	92	33
September 19	75.9	49.8	98	29
September 20	75.4	49.3	97	32
September 21	74.9	48.8	96	29
September 22	74.6	48.4	94	25
September 23	74.3	48.0	91	25
September 24	74.0	47.6	89	30
September 25	73.6	47.2	93	31
September 26	73.2	46.7	93	25
September 27	72.8	46.2	93	29
September 28	72.4	45.8	90	27
September 29	72.0	45.3	95	25
September 30	71.5	44.9	94	28

Weather Station Details

Years	Station	Coordinates
1948–2024	Sioux City Gateway Airport	location