September weather forecastSun Prairie, WI
September
Weather in September
September’s weather in Sun Prairie, Wisconsin, begins to dip into the early notes of autumn, setting itself apart from the fading summer. A noticeable shift from the high temperatures of the previous months is visible with September's average high dropping down to 70.7°F (21.5°C). Fall colors start to adorn the trees, and the air begins to gift an early autumn chill. Sunset arrives earlier, yet the weather remains perfect for evening walks and outdoor dinner parties.Temperature
A subtle change in temperatures is noted in Sun Prairie, Wisconsin, as August gives way to September, with average highs reducing from a moderately hot 77.2°F (25.1°C) to a pleasant 70.7°F (21.5°C). In Sun Prairie, the average temperature during the nights of September drops to a fresh 52°F (11.1°C).Humidity
The average relative humidity in September in Sun Prairie is 81%.Rainfall
In Sun Prairie, during September, the rain falls for 12.5 days and regularly aggregates up to 2.44" (62mm) of precipitation. In Sun Prairie, during the entire year, the rain falls for 138.5 days and collects up to 26.42" (671mm) of precipitation.Snowfall
In Sun Prairie, snow does not fall in May through September.Daylight
In Sun Prairie, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:31 pm. On the last day of September, in Sun Prairie, sunrise is at 6:53 am and sunset at 6:39 pm CDT.
Sunshine
In September, the average sunshine is 8.6h.UV index
In Sun Prairie, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: A daily high UV index of 3 in September leads to these guidelines:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. The solar radiation around mid-day is intense; avoid the Sun and stay safe. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sun Prairie, WI
- Average high temperature in September: 70.7°F
The warmest month (with the highest average high temperature) is July (78.6°F).
The month with the lowest average high temperature is January (23.4°F).
- Average low temperature in September: 52°F
The month with the highest average low temperature is July (61.5°F).
The coldest month (with the lowest average low temperature) is January (10.9°F).
Average pressure in September
Sun Prairie, WI
- Average pressure in September: 30.03"Hg
The months with the highest atmospheric pressure are January and February (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Sun Prairie, WI
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is April (10.1mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).
Average humidity in September
Sun Prairie, WI
- Average humidity in September: 81%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is April (76%).
Average rainfall in September
Sun Prairie, WI
- Average rainfall in September: 2.44"
The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is February (1.1").
Average rainfall days in September
Sun Prairie, WI
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (4.7 days).
Average snowfall in September
Sun Prairie, WI
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.04").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Sun Prairie, WI
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (14.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Sun Prairie, WI
- 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 0min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 18min).
Average sunshine days in September
Sun Prairie, WI
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is December (16.8 days).
The month with the least sunshine days is June (10.8 days).
Average UV index in September
Sun Prairie, WI
- Average UV index in September: 3
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, November and December (UV index 1).
Average cloud cover in September
Sun Prairie, WI
- Average cloud cover in September: 35
The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 33).
Average visibility in September
Sun Prairie, WI
- Average visibility in September: 5mi
The months with the highest visibility are March, April, May, June, October and November (6mi).
The months with the lowest visibility are January, February, July, August, September and December (5mi).
