Illinois weather in December 2025

Expect daytime maximum temperatures of 2°C in 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°C maximum daytime temperature in December in Illinois (Chicago)2
    2°C max day temperature
  • 3 hours of sunshine per day
  • 12 days with some rainfall in December in Illinois (Chicago)12
    12 days with some rainfall
  • -7°C minimum night-time temperature in December in Illinois (Chicago)-7
    -7°C min night temperature
  • 9 hours of daylight per day in December in Illinois (Chicago)9
    9 hours of daylight per day
  • No heat & humidity in December in Illinois (Chicago)0
    No heat & humidity
  • 62 mm monthly rainfall in December in Illinois (Chicago)62
    62 mm of monthly rainfall
  • UV (maximum) index 1 (Low) in December in Illinois (Chicago)1
    1 (Low) UV index
  • 5°C sea temperature in December in Illinois (Chicago)5
    5°C sea temperature

More about Illinois

Illinois by month

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

Recommended for Illinois

TUI discount code: up to £300 off 2025/2026 holidays

  • Save up to £300 on package holidays in 2025/2026
  • Book in TUI sale. Discount varies by spend. T&Cs apply
  • Travel between 1st May 2025 & 31st Oct 2026 (inclusive)
Show discount codeShow discount code ******ALE
Redeem TUI discount code >>

Expires at 10:00 on Friday 28th Feb 2025 · View all TUI offers

TUITUI deal finder

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.

Top Illinois destinations

Below are average maximum temperatures at popular countries, regions and places in Illinois in December. Select a holiday destination to see more weather parameters.

All Illinois destinations

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

Back to top

More about the USA

How cold is it in Illinois in December?

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

How sunny is it in Illinois in December?

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

Is the sea cold around Illinois in December?

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

Does it rain in Illinois in December?

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

Illinois December sunrise & sunset times

Browse the sunrise and sunset times for Illinois in December 2025. 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.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st December 2025 06:59 16:20
Tuesday, 16th December 2025 07:12 16:21
Wednesday, 31st December 2025 07:18 16:30

Related posts

Popular travel offers

Explore holidays in the sun for less

More holidays

Airport parking

More parking

Airport lounges

More lounges

Top ^