September weather in South Sioux City, NE
The average temperature in South Sioux City in September is 64.1°F (50.9°F–77.3°F). Average precipitation: 2.99 inches.
September is a fall month in South Sioux City, and is warmer than the annual average of 48°F. Daily temperatures swing about 26.4°F between overnight low and afternoon high. Daylight averages about 12h 16m. For travel, September is one of the best months of the year to visit.
Avg High
77.3°F
Avg Low
50.9°F
Precipitation
2.99 in
Daylight
12h 16m
September records in South Sioux City
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 102.0°F (2012) | 52.0°F (2024) | 1.15 in (2014) |
| September 2 | 93.0°F (2012) | 50.0°F (2024) | 0.15 in (2025) |
| September 3 | 102.0°F (2023) | 50.0°F (2020) | 0.97 in (2021) |
| September 4 | 100.0°F (2023) | 44.1°F (2025) | 0.13 in (2018) |
| September 5 | 98.1°F (2023) | 45.0°F (2025) | 2.60 in (2018) |
| September 6 | 91.0°F (2020) | 42.1°F (2025) | 0.02 in (2018) |
| September 7 | 93.0°F (2020) | 39.0°F (2025) | 0.38 in (2016) |
| September 8 | 89.1°F (2013) | 39.9°F (2025) | 0.19 in (2020) |
| September 9 | 91.9°F (2022) | 43.0°F (2020) | 1.05 in (2020) |
| September 10 | 93.9°F (2013) | 43.0°F (2020) | 0.42 in (2022) |
| September 11 | 93.9°F (2013) | 45.0°F (2020) | 2.15 in (2019) |
| September 12 | 97.0°F (2012) | 42.1°F (2014) | 0.61 in (2014) |
| September 13 | 89.1°F (2011) | 37.9°F (2014) | 0.41 in (2012) |
| September 14 | 93.0°F (2025) | 37.0°F (2014) | 0.00 in (2011) |
| September 15 | 90.0°F (2017) | 36.0°F (2011) | 0.93 in (2019) |
| September 16 | 90.0°F (2018) | 35.1°F (2011) | 0.62 in (2016) |
| September 17 | 91.0°F (2021) | 39.9°F (2014) | 0.81 in (2025) |
| September 18 | 93.0°F (2018) | 37.9°F (2012) | 0.15 in (2021) |
| September 19 | 89.1°F (2013) | 35.1°F (2012) | 2.20 in (2018) |
| September 20 | 90.0°F (2022) | 41.0°F (2015) | 2.17 in (2018) |
| September 21 | 98.1°F (2022) | 39.9°F (2013) | 0.11 in (2021) |
| September 22 | 90.0°F (2016) | 37.0°F (2011) | 1.82 in (2023) |
| September 23 | 93.9°F (2017) | 30.9°F (2012) | 0.25 in (2015) |
| September 24 | 90.0°F (2016) | 28.9°F (2012) | 1.03 in (2015) |
| September 25 | 90.0°F (2016) | 37.9°F (2021) | 1.21 in (2016) |
| September 26 | 84.9°F (2020) | 35.1°F (2018) | 0.98 in (2017) |
| September 27 | 89.1°F (2013) | 35.1°F (2012) | 0.00 in (2011) |
| September 28 | 90.0°F (2021) | 33.1°F (2012) | 0.11 in (2013) |
| September 29 | 91.9°F (2021) | 35.1°F (2012) | 0.46 in (2015) |
| September 30 | 93.0°F (2023) | 37.9°F (2017) | 0.30 in (2021) |