Illinois climate guide: monthly weather averages

The Illinois climate guides are perfect for planning your holiday. Monthly weather averages give the best indication of what the weather is usually like for every month of the year including figures for temperature, rainfall and sunshine. The climate guide shown below is for Chicago.

Temperature in Illinois (°C)

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max temperature (daytime)
Min temperature (night-time)
Sea temperature

Sunshine & Daylight in Illinois

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daily hours of sunshine
Daily hours of daylight

Rainfall in Illinois

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Number of days with some rain
Average monthly rainfall (mm)

More climate for Illinois

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (Maximum)
Heat & Humidity

Note: 0 = None, L = Low, M = Moderate, H = High, VH = Very high, E = Extreme

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

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More about Illinois

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

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Illinois climate by month

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

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

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