September weather forecastVermillion, SD
September
Weather in September
Vermillion in September stands on the brink of transition, sliding gently from the remaining summer heat into the arms of Fall. Cooler temperature highs become frequent, reshaping the weather towards the Fall season. Cloud cover begins to increase, shadowing the golden summer sunshine and resulting in shorter daylight hours. Despite this, the highly comfortable temperatures make this month among the best for outdoor activity. As the city leaves the cradle of summer, the weather patterns in September pave the way for Fall's calm embrace.Temperature
September's arrival coincides with a soft drop in the average high-temperature, subtly decreasing from August's moderately hot 82.4°F (28°C) to a still warm 76.1°F (24.5°C). Vermillion, during September, witnesses an average low-temperature of 54.9°F (12.7°C).Humidity
The average relative humidity in September is 69%.Rainfall
In Vermillion, in September, during 10.7 rainfall days, 1.85" (47mm) of precipitation is typically accumulated. In Vermillion, during the entire year, the rain falls for 116.6 days and collects up to 21.26" (540mm) of precipitation.Snowfall
In Vermillion, snow does not fall in June through September.Daylight
In Vermillion, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:53 am and sunset at 8:01 pm. On the last day of September, sunrise is at 7:24 am and sunset at 7:10 pm CDT.
Sunshine
The average sunshine in September is 8.9h.UV index
In Vermillion, South Dakota, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The daily high UV index of 5 during September translates into the following recommendations:
Take necessary precautions - Protection from skin and eye injury is mandatory. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Vermillion, SD
- Average high temperature in September: 76.1°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 (26.8°F).
- Average low temperature in September: 54.9°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 (12.9°F).
Average pressure in September
Vermillion, 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 (29.85"Hg).
Average wind speed in September
Vermillion, SD
- Average wind speed in September: 9.1mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.8mph).
Average humidity in September
Vermillion, SD
- Average humidity in September: 69%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (65%).
Average rainfall in September
Vermillion, SD
- Average rainfall in September: 1.85"
The wettest month (with the highest rainfall) is June (3.35").
The driest months (with the least rainfall) are January and February (0.63").
Average rainfall days in September
Vermillion, SD
- Average rainfall days in September: 10.7 days
The month with the highest number of rainy days is June (17.3 days).
The months with the least rainy days are January and February (2.8 days).
Average snowfall in September
Vermillion, SD
- Average snowfall in September: 0"
The months with the highest snowfall are January and February (2.83").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Vermillion, SD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (7.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Vermillion, 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 54min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days in September
Vermillion, SD
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is June (10.3 days).
Average UV index in September
Vermillion, SD
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Vermillion, SD
- Average cloud cover in September: 27
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 25).
Average visibility in September
Vermillion, 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).
