September weather forecast
South Sioux City, NE

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Weather in September

September sees a subtle shift in South Sioux City's weather from glaring summer to welcoming fall season. Notable is a drop in daytime temperatures, now averaging 75.6°F (24.2°C). While the weather remains moderately hot, the clear blue skies against the backdrop of burnt-orange leaves begin to transform the landscape. As September proceeds, the gradual cooling trend is complemented by shorter daylight hours. South Sioux City, in September, offers a comfortable mix of summer and autumn, attracting visitors for pleasant outdoor experiences.

Temperature

South Sioux City's transition into September involves a gentle shift in temperature, receding from 81.9°F (27.7°C) in August to a still warm 75.6°F (24.2°C). South Sioux City's average low-temperature during September nights is observed to be a refreshing 55.4°F (13°C).

Humidity

In September, the average relative humidity is 71%.

Rainfall

In September, the rain falls for 9.7 days. Throughout September, 1.26" (32mm) of precipitation is accumulated. In South Sioux City, during the entire year, the rain falls for 102.3 days and collects up to 12.91" (328mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In South Sioux City, the average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:51 am and sunset at 7:59 pm. On the last day of September, sunrise is at 7:22 am and sunset at 7:08 pm CDT.

Sunshine

In September, the average sunshine is 8.9h.

UV index

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index, 4 during September, leads to the following recommendations:
Make use of precautions - Suggestions to resist sunburn are communicated. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Updated: Aug 15, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

The average high-temperature and low-temperature during September are 75.6°F (24.2°C) and 55.4°F (13°C) respectively. In August, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, is computed to be 87.8°F (31°C).

What is the average humidity in September?

In South Sioux City, the average relative humidity in September is 71%.

How much does it rain in September?

In South Sioux City, in September, it is raining for 9.7 days, with typically 1.26" (32mm) of accumulated precipitation.

When it does not snow?

In South Sioux City, snow does not fall in May through September.

Does it snow in September?

In South Sioux City, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In South Sioux City, the average day length in September is 12h and 28min.

When are sunrise and sunset in September in South Sioux City?

On the first day of September, sunrise is at 6:51 am and sunset at 7:59 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:08 pm CDT.

How many hours of sunshine does South Sioux City have in September?

In September, the average sunshine duration is 8.9h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
South Sioux City, NE

Average temperature in September - South Sioux City, NE
  • Average high temperature in September: 75.6°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (27°F).

  • Average low temperature in September: 55.4°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).

Average pressure in September
South Sioux City, NE

Average pressure in September - South Sioux City, NE
  • Average pressure in September: 29.99"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

Average wind speed in September
South Sioux City, NE

Average wind speed in September - South Sioux City, NE
  • Average wind speed in September: 8.9mph

The windiest month (with the highest average wind speed) is April (11mph).
The calmest month (with the lowest average wind speed) is July (7.5mph).

Average humidity in September
South Sioux City, NE

Average humidity in September - South Sioux City, NE
  • Average humidity in September: 71%

The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (65%).

Average rainfall in September
South Sioux City, NE

Average rainfall in September - South Sioux City, NE
  • Average rainfall in September: 1.26"

The wettest month (with the highest rainfall) is June (1.85").
The driest months (with the least rainfall) are January and February (0.39").

Average rainfall days in September
South Sioux City, NE

Average rainfall days in September - South Sioux City, NE
  • Average rainfall days in September: 9.7 days

The month with the highest number of rainy days is June (14.6 days).
The month with the least rainy days is January (2.6 days).

Average snowfall in September
South Sioux City, NE

Average snowfall in September - South Sioux City, NE
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.77").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
South Sioux City, NE

Average snowfall days in September - South Sioux City, NE
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (8.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
South Sioux City, NE

Average daylight in September / Average sunshine in September - South Sioux City, NE
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

Average sunshine days in September
South Sioux City, NE

Average sunshine days in September - South Sioux City, NE
  • Average sunshine days in September: 17.5 days

The month with the most sunshine days is January (22.6 days).
The month with the least sunshine days is June (13.1 days).

Average UV index in September
South Sioux City, NE

Average UV index in September - South Sioux City, NE
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).

Average cloud cover in September
South Sioux City, NE

Average cloud cover in September - South Sioux City, NE
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 25).

Average visibility in September
South Sioux City, NE

Average visibility in September - South Sioux City, NE
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

South Sioux City, Nebraska, USA

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