September weather forecast
West Chicago, IL

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Weather in September

The first month of the autumn, September, is still a warm month in West Chicago, Illinois, with an average temperature ranging between max 73.4°F (23°C) and min 56.5°F (13.6°C).

Temperature

During the shift to September, West Chicago records a mild decrease in average high-temperature, moving from a moderately hot 79.5°F (26.4°C) in August to a still warm 73.4°F (23°C). During September, the temperature is averaged to a low of 56.5°F (13.6°C) at night.

Humidity

In September, the average relative humidity is 78%.

Rainfall

In West Chicago, in September, it is raining for 9.5 days, with typically 0.71" (18mm) of accumulated precipitation. In West Chicago, during the entire year, the rain falls for 101.9 days and collects up to 8.58" (218mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

The average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:19 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:35 pm CDT.

Sunshine

In September, the average sunshine in West Chicago is 8.8h.

UV index

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for average individuals.
Note: The average daily UV index of 4 in September transforms into the following instructions:
Put precautions into practice - Ensuring skin and eye safety is a necessity. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

In September, in West Chicago, the average high-temperature is 73.4°F (23°C), and the average low-temperature is 56.5°F (13.6°C). The average heat index (a.k.a. 'feels like', 'real feel'), which represents the influence of relative humidity on air temperature, in July is calculated to be 86°F (30°C).

What is the average humidity in September?

The average relative humidity in September is 78%.

How much does it rain in September?

In West Chicago, during September, the rain falls for 9.5 days and regularly aggregates up to 0.71" (18mm) of precipitation.

When it does not snow?

In West Chicago, snow does not fall in May through September.

Does it snow in September?

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

How many hours of daylight does West Chicago have in September?

The average day length in September is 12h and 28min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:19 am and sunset at 7:25 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:35 pm CDT.

How long on average sun shines in September?

In West Chicago, the average sunshine duration in September is 8.8h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health 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
West Chicago, IL

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

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (27.9°F).

  • Average low temperature in September: 56.5°F

The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).

Average pressure in September
West Chicago, IL

Average pressure in September - West Chicago, 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
West Chicago, IL

Average wind speed in September - West Chicago, IL
  • Average wind speed in September: 7.1mph

The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

Average humidity in September
West Chicago, IL

Average humidity in September - West Chicago, IL
  • Average humidity in September: 78%

The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (74%).

Average rainfall in September
West Chicago, IL

Average rainfall in September - West Chicago, IL
  • Average rainfall in September: 0.71"

The wettest month (with the highest rainfall) is May (1.26").
The driest months (with the least rainfall) are November and December (0.39").

Average rainfall days in September
West Chicago, IL

Average rainfall days in September - West Chicago, IL
  • Average rainfall days in September: 9.5 days

The month with the highest number of rainy days is May (12.4 days).
The month with the least rainy days is January (3.4 days).

Average snowfall in September
West Chicago, IL

Average snowfall in September - West Chicago, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.14").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
West Chicago, IL

Average snowfall days in September - West Chicago, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
West Chicago, IL

Average daylight in September / Average sunshine in September - West Chicago, 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 month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in September
West Chicago, IL

Average sunshine days in September - West Chicago, IL
  • Average sunshine days in September: 17.7 days

The month with the most sunshine days is December (22.4 days).
The month with the least sunshine days is June (13.3 days).

Average UV index in September
West Chicago, IL

Average UV index in September - West Chicago, 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
West Chicago, IL

Average cloud cover in September - West Chicago, IL
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is September (Cloud cover 32).

Average visibility in September
West Chicago, IL

Average visibility in September - West Chicago, IL
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).

West Chicago, Illinois, USA

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