Illinois weather averages

Going to Illinois? Find the best month to visit Illinois based on the weather.

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Check Illinois weather averages before you book your next holiday in 2019/2020. Today's maximum temperature in Illinois is expected to be 6°C, while the average maximum temperature in February is 1°C. The holiday weather guide shown above is for Chicago.

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More about Illinois

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The weather for Illinois, represented by Chicago, shows long term weather averages processed from data supplied by CRU (University of East Anglia) & today's weather forecast provided by MeteoBlue. Find out more about our data sources.

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

Illinois weather averages: best month

Illinois Best month Averages
Warmest July 29°C
Sunniest June & July 10 hours per day
Least rain August, September & October 9 days
Warmest sea August 21°C

Illinois climate guide

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Tropical storm risk: Illinois hurricane season

% of month affected by tropical storms
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The Illinois tropical storm risk chart above shows the hurricane season for Chicago, Illinois. The chart was processed from data supplied by the US Meteorological Agency (NOAA). Find out more about our data sources.

More about tropical storms

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Illinois weather averages by month

Check Illinois holiday weather averages for a particular month by selecting from the list below. Monthly weather guides include figures for temperature, rainfall, sunshine hours and sea temperature plus daily sunrise & sunset times.

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Compare Illinois weather with the USA

Below the Illinois weather chart shows maximum daytime temperature for Illinois, USA (Chicago) and the USA (Washington). For more weather parameters or to change the destinations shown visit the comparison weather tool.

Maximum daytime temperature (°C)

Illinois, USA (Chicago)
USA (Washington)
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Metric (°C / mm)  |  Imperial (°F / inches)

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More Illinois destinations

All Illinois destinations >>

All destinations (A to Z)

Can't see your chosen destination? Use our A to Z search to find your required the holiday weather guide:

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