September weather forecast
Chicago Heights, IL

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Weather in September

September, the first month of the autumn in Chicago Heights, is still a warm month, with temperature in the range of an average high of 73.9°F (23.3°C) and an average low of 58.3°F (14.6°C).

Temperature

Chicago Heights's weather in September involves a mild decrease in the average high-temperature, moving down slightly from August's moderately hot 80.1°F (26.7°C) to a still warm 73.9°F (23.3°C). An average minimum temperature of 58.3°F (14.6°C) is recorded during the month of September.

Humidity

The average relative humidity in September is 76%.

Rainfall

In Chicago Heights, in September, during 13.4 rainfall days, 2.48" (63mm) of precipitation is typically accumulated. In Chicago Heights, during the entire year, the rain falls for 155.6 days and collects up to 31.3" (795mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 28min.
On the first day of September in Chicago Heights, Illinois, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:33 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 reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: The UV index of 4 during September translates into the following guidance:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Updated: Aug 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Chicago Heights in September?

In September, in Chicago Heights, the average high-temperature is 73.9°F (23.3°C), and the average low-temperature is 58.3°F (14.6°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in July is evaluated at 87.8°F (31°C).

What is the average humidity in September?

In Chicago Heights, the average relative humidity in September is 76%.

How much does it rain in September?

In Chicago Heights, Illinois, in September, it is raining for 13.4 days, with typically 2.48" (63mm) of accumulated precipitation.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

In Chicago Heights, 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 28min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:33 pm CDT.

How long on average sun shines in September?

The average sunshine duration in September is 8.8h.

How high is the UV index in September?

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

Average temperature in September - Chicago Heights, IL
  • Average high temperature in September: 73.9°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure in September
Chicago Heights, IL

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

Average wind speed in September - Chicago Heights, IL
  • Average wind speed in September: 7.3mph

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
Chicago Heights, IL

Average humidity in September - Chicago Heights, IL
  • Average humidity in September: 76%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).

Average rainfall in September
Chicago Heights, IL

Average rainfall in September - Chicago Heights, IL
  • Average rainfall in September: 2.48"

The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").

Average rainfall days in September
Chicago Heights, IL

Average rainfall days in September - Chicago Heights, IL
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).

Average snowfall in September
Chicago Heights, IL

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

The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Chicago Heights, IL

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

The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 6min).
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 August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

Average sunshine days in September
Chicago Heights, IL

Average sunshine days in September - Chicago Heights, IL
  • Average sunshine days in September: 14 days

The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).

Average UV index in September
Chicago Heights, IL

Average UV index in September - Chicago Heights, IL
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in September
Chicago Heights, IL

Average cloud cover in September - Chicago Heights, 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 August (Cloud cover 30).

Average visibility in September
Chicago Heights, IL

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

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

Chicago Heights, Illinois, USA

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