September weather forecast
Vergennes, IL

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Vergennes, Illinois, with an average temperature varying between 79.7°F (26.5°C) and 60.1°F (15.6°C).

Temperature

September's arrival comes with a mild decrease in the average high-temperature, moving subtly from a moderately hot 85.5°F (29.7°C) in August to a still warm 79.7°F (26.5°C). In the month of September, Vergennes witnesses a consistent average low-temperature of 60.1°F (15.6°C).

Humidity

In Vergennes, the average relative humidity in September is 74%.

Rainfall

In Vergennes, during September, the rain falls for 11.6 days and regularly aggregates up to 1.73" (44mm) of precipitation. Throughout the year, there are 147.6 rainfall days, and 29.17" (741mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall.

Daylight

In Vergennes, the average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:52 am and sunset at 6:41 pm CDT.

Sunshine

The average sunshine in September is 9.2h.

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Stay sun-safe with clothing that is both closely woven and worn loosely.
Updated: Jul 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Vergennes in September?

In September, the average high-temperature and low-temperature in Vergennes are 79.7°F (26.5°C) and 60.1°F (15.6°C) respectively. The average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, in August is evaluated at 96.8°F (36°C).

What is the average humidity in September?

In Vergennes, the average relative humidity in September is 74%.

How much does it rain in September?

In Vergennes, during September, the rain falls for 11.6 days and regularly aggregates up to 1.73" (44mm) of precipitation.

When it does not snow?

In Vergennes, snow does not fall in May through October.

What is the average length of the day in September?

The average day length in September is 12h and 25min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:27 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:41 pm CDT.

How many hours of sunshine does Vergennes have in September?

The average sunshine duration in September is 9.2h.

What is the UV index reading in September?

The average daily maximum UV index in September in Vergennes is 5. A UV Index estimate of 3 to 5 represents a medium health risk from exposure to the Sun's UV radiation.
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
Vergennes, IL

Average temperature in September - Vergennes, IL
  • Average high temperature in September: 79.7°F

The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (38.8°F).

  • Average low temperature in September: 60.1°F

The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

Average pressure in September
Vergennes, IL

Average pressure in September - Vergennes, IL
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Vergennes, IL

Average wind speed in September - Vergennes, IL
  • Average wind speed in September: 6.3mph

The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

Average humidity in September
Vergennes, IL

Average humidity in September - Vergennes, IL
  • Average humidity in September: 74%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).

Average rainfall in September
Vergennes, IL

Average rainfall in September - Vergennes, IL
  • Average rainfall in September: 1.73"

The wettest month (with the highest rainfall) is April (3.58").
The driest month (with the least rainfall) is January (1.5").

Average rainfall days in September
Vergennes, IL

Average rainfall days in September - Vergennes, IL
  • Average rainfall days in September: 11.6 days

The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is December (8.2 days).

Average snowfall in September
Vergennes, IL

Average snowfall in September - Vergennes, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is February (1.5").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Vergennes, IL

Average snowfall days in September - Vergennes, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (5.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Vergennes, IL

Average daylight in September / Average sunshine in September - Vergennes, IL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in September
Vergennes, IL

Average sunshine days in September - Vergennes, IL
  • Average sunshine days in September: 16.7 days

The months with the most sunshine days are October and November (19.5 days).
The month with the least sunshine days is May (11.4 days).

Average UV index in September
Vergennes, IL

Average UV index in September - Vergennes, IL
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Vergennes, IL

Average cloud cover in September - Vergennes, IL
  • Average cloud cover in September: 29

The months with the most cloud cover are January and February (Cloud cover 50).
The month with the least cloud cover is June (Cloud cover 28).

Average visibility in September
Vergennes, IL

Average visibility in September - Vergennes, IL
  • 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).

Vergennes, Illinois, USA

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