September weather forecast
Sun Prairie, WI

Share

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.
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September in Sun Prairie?

Sun Prairie in September has an average high-temperature of 70.7°F (21.5°C) and an average low-temperature of 52°F (11.1°C).

What is the average humidity in September in Sun Prairie?

In September, the average relative humidity in Sun Prairie is 81%.

How many days does it rain in September in Sun Prairie?

In September, in Sun Prairie, the rain falls for 12.5 days. Throughout September, 2.44" (62mm) of precipitation is accumulated.

When it does not snow in Sun Prairie?

May through September are months without snowfall in Sun Prairie.

Does it snow in Sun Prairie in September?

In Sun Prairie, Wisconsin, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Sun Prairie have in September?

In September, the average day length in Sun Prairie, Wisconsin, is 12h and 29min.

When are sunrise and sunset in September in Sun Prairie?

On the first day of September, sunrise is at 6:21 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:39 pm CDT.

How long on average sun shines in September in Sun Prairie?

In September, the average sunshine duration is 8.6h.

What is the UV index intensity in September in Sun Prairie?

The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium health risk from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Sun Prairie, WI

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in September - Sun Prairie, WI
  • Average daylight in September: 12h and 3min

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 4min

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 - 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 - 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 - 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 - 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).

Sun Prairie, Wisconsin, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location