September weather forecastRapid Valley, SD
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Rapid Valley, South Dakota, with an average temperature ranging between min 54°F (12.2°C) and max 73.9°F (23.3°C).Temperature
With the onset of September, Rapid Valley's climate undergoes a slight change as the average high-temperature moves from a moderately hot 82.8°F (28.2°C) in August to a still warm 73.9°F (23.3°C). Rapid Valley experiences a nighttime temperature average of 54°F (12.2°C) during September.Humidity
August and September, with an average relative humidity of 50%, are the least humid months.Rainfall
In Rapid Valley, in September, it is raining for 7.8 days, with typically 0.94" (24mm) of accumulated precipitation. Throughout the year, there are 118.8 rainfall days, and 15.39" (391mm) of precipitation is accumulated.Snowfall
Months with snowfall in Rapid Valley are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.12" (3mm) of snow. Throughout the year, there are 50.4 snowfall days, and 24.41" (620mm) of snow is accumulated.Daylight
The average length of the day in September in Rapid Valley is 12h and 29min.On the first day of September in Rapid Valley, sunrise is at 6:16 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:34 pm MDT.
Sunshine
In Rapid Valley, the average sunshine in September is 10.4h.UV index
The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: The daily maximum UV index of 4 in September interprets into the following advice:
Exercise care. People with light skin might get burns in fewer than 30 minutes. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Rapid Valley, SD
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is December (32.5°F).
- Average low temperature in September: 54°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is February (17.8°F).
Average pressure in September
Rapid Valley, SD
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in September
Rapid Valley, SD
- Average wind speed in September: 9.1mph
The windiest month (with the highest average wind speed) is April (10.3mph).
The calmest month (with the lowest average wind speed) is August (8.2mph).
Average humidity in September
Rapid Valley, SD
- Average humidity in September: 50%
The month with the highest relative humidity is January (77%).
The months with the lowest relative humidity are August and September (50%).
Average rainfall in September
Rapid Valley, SD
- Average rainfall in September: 0.94"
The wettest month (with the highest rainfall) is May (2.28").
The driest month (with the least rainfall) is January (0.43").
Average rainfall days in September
Rapid Valley, SD
- Average rainfall days in September: 7.8 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is December (4.8 days).
Average snowfall in September
Rapid Valley, SD
- Average snowfall in September: 0.12"
The month with the highest snowfall is April (5.43").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Rapid Valley, SD
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is February (10.5 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Rapid Valley, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 10h and 24min
The month with the most sunshine is August (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 54min).
Average sunshine days in September
Rapid Valley, SD
- Average sunshine days in September: 19.9 days
The month with the most sunshine days is November (20.2 days).
The month with the least sunshine days is May (11 days).
Average UV index in September
Rapid Valley, 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).
Average cloud cover in September
Rapid Valley, SD
- Average cloud cover in September: 18
The months with the most cloud cover are February and April (Cloud cover 38).
The month with the least cloud cover is August (Cloud cover 16).
Average visibility in September
Rapid Valley, 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).
