September weather forecast
Addison, IL

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Weather in September

September, the first month of the autumn in Addison, is also a moderately hot month, with an average temperature fluctuating between 73.4°F (23°C) and 58.6°F (14.8°C).

Temperature

The onset of September entails a subtle temperature shift, as the average high-temperature eases from 80.2°F (26.8°C) in August to a still warm 73.4°F (23°C). During September nights, Addison records an average temperature of 58.6°F (14.8°C).

Humidity

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

Rainfall

In Addison, in September, during 13.5 rainfall days, 1.89" (48mm) of precipitation is typically accumulated. Throughout the year, there are 149.4 rainfall days, and 25.08" (637mm) of precipitation is accumulated.

Snowfall

In Addison, snow does not fall in June through September.

Daylight

In Addison, the average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:18 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:34 pm CDT.

Sunshine

The average sunshine in September is 8.8h.

UV index

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for average individuals.
Note: The daily maximum UV index of 4 in September interprets into the following advice:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Experience reduced UV exposure by about half when donning a wide-brim hat.
Updated: Jul 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in September?

The high-temperature during September is 73.4°F (23°C) and the low-temperature is 58.6°F (14.8°C). In July, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines air temperature and relative humidity, is evaluated at 87.8°F (31°C).

What is the average humidity in September?

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

How much does it rain in September?

In Addison, in September, it is raining for 13.5 days, with typically 1.89" (48mm) of accumulated precipitation.

When it does not snow?

June through September are months without snowfall in Addison, Illinois.

Does it snow in September?

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

How many hours of daylight does Addison have in September?

In Addison, the average day length in September is 12h and 28min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:18 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.

How many hours of sunshine does Addison have in September?

The average sunshine duration in September is 8.8h.

What is the UV index reading in September?

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unsafe 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
Addison, IL

Average temperature in September - Addison, IL
  • Average high temperature in September: 73.4°F

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (28.8°F).

  • Average low temperature in September: 58.6°F

The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (18°F).

Average pressure in September
Addison, IL

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

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Addison, IL

Average wind speed in September - Addison, IL
  • Average wind speed in September: 7.5mph

The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).

Average humidity in September
Addison, IL

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

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

Average rainfall in September
Addison, IL

Average rainfall in September - Addison, IL
  • Average rainfall in September: 1.89"

The wettest month (with the highest rainfall) is May (3.11").
The driest month (with the least rainfall) is December (1.14").

Average rainfall days in September
Addison, IL

Average rainfall days in September - Addison, IL
  • Average rainfall days in September: 13.5 days

The months with the highest number of rainy days are May and July (17.3 days).
The month with the least rainy days is February (5.1 days).

Average snowfall in September
Addison, IL

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

The month with the highest snowfall is February (3.86").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Addison, IL

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

The month with the highest number of snowfall days is January (12.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in September / Average sunshine in September - Addison, IL
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 8h and 5min

The months with the most sunshine are July and August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in September
Addison, IL

Average sunshine days in September - Addison, IL
  • Average sunshine days in September: 13 days

The month with the most sunshine days is November (16.8 days).
The month with the least sunshine days is July (9.5 days).

Average UV index in September
Addison, IL

Average UV index in September - Addison, IL
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September
Addison, IL

Average cloud cover in September - Addison, IL
  • Average cloud cover in September: 31

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in September
Addison, IL

Average visibility in September - Addison, 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).

Addison, Illinois, USA

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