September weather forecast
Dahlgren, IL

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Weather in September

The first month of the autumn, September, is still a warm month in Dahlgren, Illinois, with an average temperature varying between 60.6°F (15.9°C) and 79.7°F (26.5°C).

Temperature

Dahlgren's shift from August to September is accompanied by an average high-temperature of a still warm 79.7°F (26.5°C), a slight deviation from 84.9°F (29.4°C). During the month of September, the temperature generally drops to a low average of 60.6°F (15.9°C).

Humidity

In Dahlgren, the average relative humidity in September is 73%.

Rainfall

September is the month with the least rainfall. Rain falls for 11.5 days and accumulates 1.57" (40mm) of precipitation.

Snowfall

In Dahlgren, Illinois, snow does not fall in May through September.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:25 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:50 am and sunset at 6:38 pm CDT.

Sunshine

The average sunshine in September is 9.3h.

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: A maximum daily UV index of 5 during September morphs into the following directions:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Updated: Jun 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

September temperatures vary between a high-temperature of 79.7°F (26.5°C) and a low-temperature of 60.6°F (15.9°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, in August is appraised at 95°F (35°C).

What is the average humidity in September?

The average relative humidity in September is 73%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 11.5 days and typically collects 1.57" (40mm) of precipitation.

How much does it rain in September?

In Dahlgren, in September, during 11.5 rainfall days, 1.57" (40mm) of precipitation is typically accumulated.

When it does not snow?

In Dahlgren, snow does not fall in May through September.

Does it snow in September?

In Dahlgren, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In September, the average day length is 12h and 25min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:25 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:38 pm CDT.

How many hours of sunshine does Dahlgren have in September?

The average sunshine duration in September in Dahlgren is 9.3h.

What is the UV index reading in September?

In Dahlgren, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to 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
Dahlgren, IL

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

The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (38.5°F).

  • Average low temperature in September: 60.6°F

The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

Average pressure in September
Dahlgren, IL

Average pressure in September - Dahlgren, 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 (29.94"Hg).

Average wind speed in September
Dahlgren, IL

Average wind speed in September - Dahlgren, IL
  • Average wind speed in September: 6.7mph

The windiest months (with the highest average wind speed) are January, February and March (9.9mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

Average humidity in September
Dahlgren, IL

Average humidity in September - Dahlgren, IL
  • Average humidity in September: 73%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).

Average rainfall in September
Dahlgren, IL

Average rainfall in September - Dahlgren, IL
  • Average rainfall in September: 1.57"

The wettest month (with the highest rainfall) is April (4.13").
The driest month (with the least rainfall) is September (1.57").

Average rainfall days in September
Dahlgren, IL

Average rainfall days in September - Dahlgren, IL
  • Average rainfall days in September: 11.5 days

The month with the highest number of rainy days is May (16.2 days).
The months with the least rainy days are January and February (8.3 days).

Average snowfall in September
Dahlgren, IL

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

The month with the highest snowfall is February (1.42").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Dahlgren, IL

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

The month with the highest number of snowfall days is January (4.8 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
Dahlgren, IL

Average daylight in September / Average sunshine in September - Dahlgren, 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 2min

The months with the most sunshine are June and July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
Dahlgren, IL

Average sunshine days in September - Dahlgren, IL
  • Average sunshine days in September: 16.4 days

The month with the most sunshine days is October (20.3 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in September
Dahlgren, IL

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

The months with the highest UV index are May, 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
Dahlgren, IL

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

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June, July and August (Cloud cover 28).

Average visibility in September
Dahlgren, IL

Average visibility in September - Dahlgren, 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).

Dahlgren, Illinois, USA

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