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Sioux City (IA)
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United States weather

Weather in Sioux City, Iowa for September 2026

Your guide to Sioux City weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Sioux City at the beginning of September is 21 °F. As the month progressed, temperatures tended to significantly warm up, reaching an average of 27.1 °F by the end of September.

    • Rain 🌧️

  • Sioux City experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 56 mm.

    • More

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Average dry days
23
Dry days
Average rainy days
7
Rainy days
Average snowy days
0
Snow days
Average temperatures
26°/13°
Temperatures
Average wind speed
22 km/h
Avg max wind
Average humidity
76 %
Avg humidity

Sioux City Weather September

Move between months or click on a day
August
October
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Moderate or heavy rain shower
20°
2
Fog
26°
3
Heavy rain at times
17°
4
Overcast
21°
5
Sunny
22°
6
Sunny
19°
7
Fog
22°
8
Overcast
26°
9
Thundery outbreaks possible
25°
10
Mist
29°
11
Overcast
29°
12
Partly cloudy
31°
13
Mist
36°
14
Overcast
29°
15
Fog
32°
16
Mist
35°
17
Patchy light rain with thunder
25°
18
Heavy rain at times
24°
19
Overcast
23°
20
Mist
23°
21
Fog
28°
22
Moderate or heavy rain shower
29°
23
Light rain shower
22°
24
Fog
24°
25
Fog
26°
26
Mist
30°
27
Mist
26°
28
Sunny
27°
29
Fog
32°
30
Mist
25°

Temperatures trend during September in Sioux City

See the weather trend as well as the moving average line

September weather in Sioux City day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
Sept. 1 Moderate or heavy rain shower
Moderate or heavy rain shower
 20° /15° 9.8 mm 5
Sept. 2 Fog
Fog
 26° /13° 0 mm 6
Sept. 3 Heavy rain at times
Heavy rain at times
 17° /11° 4.1 mm 4
Sept. 4 Overcast
Overcast
 21° /8° 0 mm 5
Sept. 5 Sunny
Sunny
 22° /7° 0.9 mm 6
Sept. 6 Sunny
Sunny
 19° /3° 0 mm 5
Sept. 7 Fog
Fog
 22° /3° 0 mm 5
Sept. 8 Overcast
Overcast
 26° /12° 0 mm 6
Sept. 9 Thundery outbreaks possible
Thundery outbreaks possible
 25° /17° 0 mm 6
Sept. 10 Mist
Mist
 29° /17° 0 mm 6
Sept. 11 Overcast
Overcast
 29° /18° 0 mm 6
Sept. 12 Partly cloudy
Partly cloudy
 31° /19° 0 mm 8
Sept. 13 Mist
Mist
 36° /16° 0 mm 8
Sept. 14 Overcast
Overcast
 29° /18° 0.2 mm 6
Sept. 15 Fog
Fog
 32° /17° 0 mm 7
Sept. 16 Mist
Mist
 35° /16° 0 mm 8
Sept. 17 Patchy light rain with thunder
Patchy light rain with thunder
 25° /19° 6.7 mm 6
Sept. 18 Heavy rain at times
Heavy rain at times
 24° /19° 17.3 mm 5
Sept. 19 Overcast
Overcast
 23° /14° 0.2 mm 5
Sept. 20 Mist
Mist
 23° /10° 0 mm 5
Sept. 21 Fog
Fog
 28° /15° 0 mm 6
Sept. 22 Moderate or heavy rain shower
Moderate or heavy rain shower
 29° /16° 12.7 mm 6
Sept. 23 Light rain shower
Light rain shower
 22° /15° 4.1 mm 5
Sept. 24 Fog
Fog
 24° /11° 0 mm 5
Sept. 25 Fog
Fog
 26° /13° 0 mm 6
Sept. 26 Mist
Mist
 30° /11° 0 mm 7
Sept. 27 Mist
Mist
 26° /13° 0 mm 6
Sept. 28 Sunny
Sunny
 27° /7° 0 mm 7
Sept. 29 Fog
Fog
 32° /13° 0 mm 7
Sept. 30 Mist
Mist
 25° /16° 0 mm 6
Next
Important Notice
Our weather forecast for Sioux City in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Sioux City forecast closer to your planned date for the most up-to-date weather information.
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Sioux City in September - FAQ

What are the expected maximum and minimum temperatures in Sioux City during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Sioux City during September?
Moderate rainfall is anticipated in Sioux City during September, with a total of 56 mm spread over approximately 7 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Sioux City during September?
The average wind speed in Sioux City during September is 22 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Sioux City

Explore the daily rainfall trends and prepare for Sioux Citys September weather 💧
Typically, Sioux City has 7 rainy days in September with a total of 56 mm of rainfall.

UV exposure in Sioux City during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

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Location coordinates Where is Sioux City?

Get accurate weather forecasts for Sioux City, located at latitude 42.5 and longitude -96.4. Stay updated with localized weather information tailored for Sioux City.

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