September weather forecast
Sioux Falls, SD

The Sioux Falls in South Dakota, flowing downstream over rocks under the perfect evening skyline
The Sioux Falls in South Dakota, flowing downstream over rocks under the perfect evening skyline

Weather in September

September, the first month of the autumn in Sioux Falls, is also a moderately hot month, with an average temperature varying between 74.3°F (23.5°C) and 53.2°F (11.8°C).

Temperature

In September, the average high-temperature marginally drops from 81.1°F (27.3°C) in August to a still warm 74.3°F (23.5°C). In September, in Sioux Falls, the average low-temperature is 53.2°F (11.8°C).

Humidity

In Sioux Falls, the average relative humidity in September is 70%.

Rainfall

In Sioux Falls, it is raining for 10.5 days, with typically 1.89" (48mm) of accumulated precipitation. Throughout the year, there are 117.1 rainfall days, and 20.71" (526mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Sioux Falls.

Daylight

In Sioux Falls, the average length of the day in September is 12h and 29min.
On the first day of September in Sioux Falls, sunrise is at 6:51 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:10 pm CDT.

Sunshine

The average sunshine in September is 8.8h.

UV index

In September, the average daily maximum UV index in Sioux Falls is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 4 in September transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in September in Sioux Falls?

In September, the average relative humidity in Sioux Falls is 70%.

How many days does it rain in September in Sioux Falls?

In Sioux Falls, during September, the rain falls for 10.5 days and regularly aggregates up to 1.89" (48mm) of precipitation.

When it does not snow in Sioux Falls?

In Sioux Falls, South Dakota, snow does not fall in June through September.

Does it snow in Sioux Falls in September?

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

What is the average length of the day in September in Sioux Falls?

The average day length in September in Sioux Falls is 12h and 29min.

When is the sunrise / sunset in September in Sioux Falls?

On the first day of September, sunrise is at 6:51 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:10 pm CDT.

How many hours of sunshine does Sioux Falls have in September?

The average sunshine duration in September is 8.8h.

What is the UV index intensity in September in Sioux Falls?

In September, the average daily maximum UV index in Sioux Falls is 4. A UV Index reading of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Sioux Falls, SD

Average temperature in September - Sioux Falls, SD
  • Average high temperature in September: 74.3°F

The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (23.4°F).

  • Average low temperature in September: 53.2°F

The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (9.7°F).

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Average pressure in September
Sioux Falls, SD

Average pressure in September - Sioux Falls, SD
  • Average pressure in September: 29.98"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).

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Average wind speed in September
Sioux Falls, SD

Average wind speed in September - Sioux Falls, SD
  • Average wind speed in September: 9.4mph

The windiest month (with the highest average wind speed) is April (11.3mph).
The calmest month (with the lowest average wind speed) is July (8mph).

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Average humidity in September
Sioux Falls, SD

Average humidity in September - Sioux Falls, SD
  • Average humidity in September: 70%

The month with the highest relative humidity is January (88%).
The month with the lowest relative humidity is October (66%).

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Average rainfall in September
Sioux Falls, SD

Average rainfall in September - Sioux Falls, SD
  • Average rainfall in September: 1.89"

The wettest month (with the highest rainfall) is June (3.27").
The driest months (with the least rainfall) are January, February and November (0.67").

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Average rainfall days in September
Sioux Falls, SD

Average rainfall days in September - Sioux Falls, SD
  • Average rainfall days in September: 10.5 days

The month with the highest number of rainy days is June (17.8 days).
The month with the least rainy days is February (3 days).

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Average snowfall in September
Sioux Falls, SD

Average snowfall in September - Sioux Falls, SD
  • Average snowfall in September: 0"

The month with the highest snowfall is February (4.25").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Sioux Falls, SD

Average snowfall days in September - Sioux Falls, SD
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Sioux Falls, SD

Average daylight in September / Average sunshine in September - Sioux Falls, SD
  • Average daylight in September: 12h and 29min

The month with the longest days is June (Average daylight: 15h and 22min).
The month with the shortest days is December (Average daylight: 9h and 1min).

  • Average sunshine in September: 8h and 48min

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 0min).

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Average sunshine days in September
Sioux Falls, SD

Average sunshine days in September - Sioux Falls, SD
  • Average sunshine days in September: 17.7 days

The month with the most sunshine days is November (20.6 days).
The month with the least sunshine days is June (10 days).

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Average UV index in September
Sioux Falls, SD

Average UV index in September - Sioux Falls, SD
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in September
Sioux Falls, SD

Average cloud cover in September - Sioux Falls, SD
  • Average cloud cover in September: 29

The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is July (Cloud cover 27).

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Average visibility in September
Sioux Falls, SD

Average visibility in September - Sioux Falls, SD
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

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