Illinois weather by month

Check out Illinois weather averages by month. Compare detailed monthly climate statistics including temperature, rainfall and sunshine figures.

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum daytime temperature °C
Hours of sunshine (daily)
Days with some rainfall
Sea temperature °C

More about Illinois

Illinois by month

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

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The climate guide for Illinois (Chicago) shows long term monthly 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 countries, regions and places in Illinois for next month - January. Select a destination to see the climate guide for all months of the year.

All Illinois destinations

Metric (°C / mm)  |  Imperial (°F / inches)

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More about the USA

Compare Illinois with the UK

Below the Illinois chart shows average maximum daytime temperature for Illinois, USA (Chicago) and the UK (London).

Maximum daytime temperature (°C)

Illinois, USA (Chicago)
UK (London)
7
1
7
8
10
15
13
21
17
27
20
29
22
28
22
24
19
17
15
9
10
2
8
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
-1

Metric (°C / mm)  |  Imperial (°F / inches)

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