Illinois weather in September 2024

Expect 75°F daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Illinois in September. Check more long-term weather averages for Illinois in September before you book your next holiday to Illinois in 2024/2025.

75
75°F max day temperature
8
8 hours of sunshine per day
9
9 days with some rainfall
54
54°F min night temperature
12
12 hours of daylight per day
0
No heat & humidity
3.4
3.4 inches of monthly rainfall
6
6 (High) UV index
66
66°F sea temperature

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The September weather guide for Illinois (Chicago) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Top Illinois destinations

Below are average maximum temperatures at popular destinations in Illinois in September. Select a destination to see more weather parameters.

79
Springfield
75
Chicago

All Illinois destinations

Metric (°C) | Imperial (°F)

More about the USA

How hot is it in Illinois in September?

Daytime temperatures usually reach 75°F in Chicago, Illinois in September, falling to 54°F at night.

How sunny is it in Illinois in September?

There are normally 8 hours of bright sunshine each day in Chicago, Illinois in September - that's 61% of daylight hours.

How warm is the sea around Illinois in September?

The average sea temperature around Chicago, Illinois in September is 66°F.

Does it rain in Illinois in September?

There are usually 9 days with some rain in Chicago, Illinois in September and the average monthly rainfall is 3.4 inches.

Illinois September sunrise & sunset times

Browse the sunrise and sunset times for Illinois in September 2024. Select a month to view Illinois sunrise and sunset times for the next 12 months. The Illinois sunrise and sunset times shown below are for Chicago.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Date	Sunrise times	Sunset times
Sunday, 1st September 2024	06:17	19:23
Sunday, 15th September 2024	06:31	18:59
Monday, 30th September 2024	06:47	18:33

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Illinois - quick facts
Flight time^✝	8.5 hours
Time difference	UK -6 hours
Language(s)	English
Currency	US Dollar
Electricity	A + B plug (120V)
Driving side	Right
Visa^✝	Yes
Why visit?	Culture
Tourist info	Illinois Department of Commerce & Economic Opportunity