Chicago weather in December 2026

Q: How cold is it in Chicago in December?

Daytime temperatures usually reach 2°C in Chicago in December, falling to -7°C at night.

Q: How sunny is it in Chicago in December?

There are normally 3 hours of bright sunshine each day in Chicago in December - that's 37% of daylight hours.

Q: Is the sea cold around Chicago in December?

The average sea temperature around Chicago in December is 5°C.

Q: Does it rain in Chicago in December?

There are usually 12 days with some rain in Chicago in December and the average monthly rainfall is 62mm. Rain may fall as snow in this month.

Expect daytime maximum temperatures of 2°C in Chicago, Illinois in December based on long-term weather averages. There are 3 hours of sunshine per day on average with 12 days with some rainfall and typically 62 mm of rainfall in the month, which might fall as snow.

2
2°C max day temperature
3
3 hours of sunshine per day
12
12 days with some rainfall
-7
-7°C min night temperature
9
9 hours of daylight per day
0
No heat & humidity
62
62 mm of monthly rainfall
1
1 (Low) UV index
5
5°C sea temperature

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The December 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.

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

More about the USA

How cold is it in Chicago in December?

Daytime temperatures usually reach 2°C in Chicago in December, falling to -7°C at night.

How sunny is it in Chicago in December?

There are normally 3 hours of bright sunshine each day in Chicago in December - that's 37% of daylight hours.

Is the sea cold around Chicago in December?

The average sea temperature around Chicago in December is 5°C.

Does it rain in Chicago in December?

There are usually 12 days with some rain in Chicago in December and the average monthly rainfall is 62mm. Rain may fall as snow in this month.