Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
River Sioux's September weather shows a modest shift in high-temperatures, falling from August's warm 82.2°F (27.9°C) to a still moderately hot 76.5°F (24.7°C). In September, the nighttime temperature in River Sioux, Iowa, lowers to an average of 56.3°F (13.5°C).Humidity
In September, the average relative humidity in River Sioux is 71%.Rainfall
In River Sioux, during September, the rain falls for 12.1 days and regularly aggregates up to 2.09" (53mm) of precipitation. In River Sioux, during the entire year, the rain falls for 125.1 days and collects up to 22.64" (575mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:50 am and sunset at 7:57 pm. On the last day of September, sunrise is at 7:20 am and sunset at 7:06 pm CDT.
Sunshine
The average sunshine in September is 9h.UV index
The average daily maximum UV index in September in River Sioux is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The maximum daily UV index of 4 in September converts into the following recommendations:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days.
Frequently asked questions
What is the temperature in September in River Sioux?
What is the average humidity in September in River Sioux?
How much does it rain in River Sioux in September?
When it does not snow in River Sioux?
Does it snow in River Sioux in September?
How many hours of daylight does River Sioux have in September?
When are sunrise and sunset in September in River Sioux?
How long on average sun shines in September in River Sioux?
What is the UV index intensity in September in River Sioux?
Average temperature in September
River Sioux, IA
- Average high temperature in September: 76.5°F
The warmest month (with the highest average high temperature) is July (84.4°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.3°F).
Average pressure in September
River Sioux, IA
- 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
River Sioux, IA
- Average wind speed in September: 8.6mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).
Average humidity in September
River Sioux, IA
- Average humidity in September: 71%
The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is October (66%).
Average rainfall in September
River Sioux, IA
- Average rainfall in September: 2.09"
The wettest month (with the highest rainfall) is May (3.5").
The driest month (with the least rainfall) is January (0.71").
Average rainfall days in September
River Sioux, IA
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is June (16.8 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
River Sioux, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.8").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
River Sioux, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
River Sioux, IA
- 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 12min).
- Average sunshine in September: 9h and 0min
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 42min).
Average sunshine days in September
River Sioux, IA
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is June (11.3 days).
Average UV index in September
River Sioux, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
River Sioux, IA
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 25).
Average visibility in September
River Sioux, IA
- 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).
River Sioux, Iowa, USA
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