September weather forecastNorth Sioux City, SD
September
Weather in September
September in North Sioux City signals the advent of autumn with temperatures beginning to fall compared to August. The cooler climate of October is hinted at throughout September, with temperatures slowly declining. Days start becoming shorter and cloud cover increases slightly. Despite these changes, rain showers remain frequent, though less so than in the wet months of June and July. Notably, September has a significant decrease in UV index, decreasing to a level of 5 from the high of 6 in the summer.Temperature
The onset of September is marked by a minor decrease in temperature, transitioning from a warm 82°F (27.8°C) in August to a still moderately hot 76.1°F (24.5°C). In September, the temperature drops to an average of 55°F (12.8°C) at night.Humidity
In September, the average relative humidity is 70%.Rainfall
In September, in North Sioux City, the rain falls for 11.8 days. Throughout September, 1.93" (49mm) of precipitation is accumulated. In North Sioux City, South Dakota, during the entire year, the rain falls for 122 days and collects up to 21.61" (549mm) of precipitation.Snowfall
In North Sioux City, snow does not fall in June through September.Daylight
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 North Sioux City, the average sunshine in September is 8.8h.UV index
In North Sioux City, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A daily maximum UV index of 5 in September translates into the following instructions:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
North Sioux City, SD
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in September: 55°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 (13.1°F).
Average pressure in September
North Sioux City, 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).
Average wind speed in September
North Sioux City, SD
- Average wind speed in September: 9mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.6mph).
Average humidity in September
North Sioux City, SD
- Average humidity in September: 70%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (65%).
Average rainfall in September
North Sioux City, SD
- Average rainfall in September: 1.93"
The wettest months (with the highest rainfall) are May and June (3.03").
The driest month (with the least rainfall) is February (0.67").
Average rainfall days in September
North Sioux City, SD
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is June (17.8 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
North Sioux City, SD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.95").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
North Sioux City, SD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
North Sioux City, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- 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 24min).
Average sunshine days in September
North Sioux City, SD
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is June (9.7 days).
Average UV index in September
North Sioux City, SD
- Average UV index in September: 5
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
North Sioux City, SD
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in September
North Sioux City, SD
- 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).
