September weather forecastCuster, SD
September
Weather in September
September in Custer marks noticeable meteorological and aesthetic shifts, different from the warm August weather. The month ushers in autumn, and as warmth starts to give way, nature adorns a new color palette. A stark decrease in temperature and rainfall from August to September also aids the onset of the fall season. The city quickly transforms into a vibrant selection of fall colors under clear skies. Despite shorter daylight hours, September in Custer remains a fantastic time to experience the beauty of the transitioning season.Temperature
As September arrives, Custer's weather displays a minor decrease in high-temperatures, transitioning from August's warm 80.1°F (26.7°C) to a pleasant 71.4°F (21.9°C). The temperature in Custer lowers to an average of 51.1°F (10.6°C) during September nights.Humidity
The months with the lowest humidity in Custer are August and September, with an average relative humidity of 52%.Rainfall
In September, the rain falls for 10 days. Throughout September, 1.22" (31mm) of precipitation is accumulated. In Custer, during the entire year, the rain falls for 135.4 days and collects up to 20.39" (518mm) of precipitation.Snowfall
January through May, September through December are months with snowfall in Custer, South Dakota. September is the first month it typically snows in Custer, South Dakota. Throughout September, in the average 0.4 snowfall days, it receives 0.35" (9mm) of snow. Throughout the year, in Custer, there are 75.1 snowfall days, and 40.24" (1022mm) of snow is accumulated.Daylight
In Custer, South Dakota, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:18 am and sunset at 7:29 pm. On the last day of September, in Custer, South Dakota, sunrise is at 6:51 am and sunset at 6:36 pm MDT.
Sunshine
In Custer, the average sunshine in September is 10.5h.UV index
In September, the average daily maximum UV index in Custer is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the average person.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Custer, SD
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is December (29.8°F).
- Average low temperature in September: 51.1°F
The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is February (16.2°F).
Average pressure in September
Custer, SD
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in September
Custer, SD
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is April (9.5mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Custer, SD
- Average humidity in September: 52%
The months with the highest relative humidity are January and February (77%).
The months with the lowest relative humidity are August and September (52%).
Average rainfall in September
Custer, SD
- Average rainfall in September: 1.22"
The wettest month (with the highest rainfall) is June (3.19").
The driest month (with the least rainfall) is January (0.47").
Average rainfall days in September
Custer, SD
- Average rainfall days in September: 10 days
The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is November (4.5 days).
Average snowfall in September
Custer, SD
- Average snowfall in September: 0.35"
The month with the highest snowfall is April (7.24").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Custer, SD
- Average snowfall days in September: 0.4 days
The month with the highest number of snowfall days is February (12.9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Custer, 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: 9h and 0min).
- Average sunshine in September: 10h and 30min
The month with the most sunshine is August (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 0min).
Average sunshine days in September
Custer, SD
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is November (19.2 days).
The month with the least sunshine days is May (7.8 days).
Average UV index in September
Custer, SD
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Custer, SD
- Average cloud cover in September: 18
The month with the most cloud cover is April (Cloud cover 38).
The month with the least cloud cover is August (Cloud cover 17).
Average visibility in September
Custer, 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).
