South Sioux City, Nebraska Weather
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Climate of South Sioux City: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in South Sioux City, with average daytime highs around 31°C. January is the coolest, when nights typically fall to about -11°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 42°C, so the seasons feel very different from each other.
The area receives about 750 mm of rain in a typical year. Most of it falls from May to June, and June is the wettest month at roughly 113 mm.
For outdoor plans and travel, July to September usually offer the most comfortable weather in South Sioux City, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | -2° | -11° | 16 mm | 83% |
| Feb | 0° | -10° | 21 mm | 79% |
| Mar | 9° | -3° | 41 mm | 72% |
| Apr | 16° | 3° | 78 mm | 67% |
| May | 22° | 10° | 104 mm | 68% |
| Jun | 28° | 16° | 113 mm | 69% |
| Jul | 31° | 19° | 80 mm | 65% |
| Aug | 30° | 17° | 95 mm | 64% |
| Sep | 25° | 12° | 83 mm | 65% |
| Oct | 16° | 4° | 60 mm | 68% |
| Nov | 8° | -2° | 30 mm | 74% |
| Dec | 0° | -8° | 29 mm | 83% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around South Sioux City. Values describe typical conditions, not a forecast.
About South Sioux City weather
South Sioux City sits within Nebraska's continental Great Plains climate, with sharp seasonal extremes, about 141 km north of Omaha. Conditions turn hot with hot summers (June–August). By December, expect cold, windy winters (December–February). This page shows live, auto-refreshing weather for South Sioux City: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/Chicago.
Frequently asked questions
South Sioux City is about 141 km north of Omaha, in Nebraska.
South Sioux City sees cold, windy winters (December–February).
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for South Sioux City's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in South Sioux City, with average daytime highs of about 31°C and nights around 19°C.
The coldest nights come in January, when the average low is about -11°C and daytime highs reach around -2°C. Frost is possible on clear, calm nights.
South Sioux City receives about 750 mm of rain in a typical year. June is the wettest month at roughly 113 mm, and the main rainy period is May to June.
July to September usually offer the most comfortable weather in South Sioux City, with mild daytime temperatures and little rain.
In November South Sioux City typically sees daytime highs near 8°C and lows near -2°C, with about 30 mm of rain over the month and average humidity around 74%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
Live temperature for South Sioux City is shown at the top of this page and refreshes automatically — see the hourly breakdown below for how it changes through the day.
South Sioux City's day-to-day weather follows the broader pattern of Nebraska described above. See the hourly weather forecast or the air quality index for more detail.