September weather forecastRoslyn, SD
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Roslyn, South Dakota, with an average temperature fluctuating between 51.3°F (10.7°C) and 71.6°F (22°C).Temperature
Roslyn records a mild change in average high-temperature during September, easing from a warm 80.1°F (26.7°C) in August to a pleasant 71.6°F (22°C). Throughout the month of September, the average temperature dips to a cool 51.3°F (10.7°C) at night.Humidity
The least humid month is September, with an average relative humidity of 66%.Rainfall
In Roslyn, in September, it is raining for 10.1 days, with typically 1.57" (40mm) of accumulated precipitation. In Roslyn, during the entire year, the rain falls for 112.9 days and collects up to 22.09" (561mm) of precipitation.Snowfall
In Roslyn, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 6:52 am and sunset at 8:07 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:11 pm CDT.
Sunshine
In September, the average sunshine is 8.8h.UV index
In Roslyn, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum UV index of 4 during September translates into these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Roslyn, SD
- Average high temperature in September: 71.6°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (18.9°F).
- Average low temperature in September: 51.3°F
The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is January (5°F).
Average pressure in September
Roslyn, SD
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is February (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Roslyn, SD
- Average wind speed in September: 10.3mph
The windiest month (with the highest average wind speed) is April (11.7mph).
The calmest month (with the lowest average wind speed) is July (8.7mph).
Average humidity in September
Roslyn, SD
- Average humidity in September: 66%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is September (66%).
Average rainfall in September
Roslyn, SD
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is July (3.58").
The driest month (with the least rainfall) is November (0.63").
Average rainfall days in September
Roslyn, SD
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is June (17.9 days).
The month with the least rainy days is February (2.3 days).
Average snowfall in September
Roslyn, SD
- Average snowfall in September: 0"
The month with the highest snowfall is December (4.53").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Roslyn, SD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (15.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Roslyn, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- 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: 3h and 12min).
Average sunshine days in September
Roslyn, SD
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is June (10.4 days).
Average UV index in September
Roslyn, 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, November and December (UV index 1).
Average cloud cover in September
Roslyn, SD
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 66).
The months with the least cloud cover are July and August (Cloud cover 27).
Average visibility in September
Roslyn, SD
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).
