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Illinois climate
Climate normals for 128 cities in Illinois — find your city, or get the regional gist.
Across the 128 cities we cover in Illinois, annual averages run 7–15°C. Annual precipitation ranges 820–1278 mm across those cities. The region spans 3 Köppen zones (Dfa · Cfa · Dfb).
Largest cities in Illinois
The most populous cities — most visitors want one of these. Tap a name for month-by-month detail.
Chicago
Population 2.7M
Hot summers, cold winters
Avg
−5°C in January, 25°C in July
Aurora
Population 201k
Warm summers, cold winters
Avg
−5°C in January, 24°C in July
Rockford
Population 148k
Warm summers, very cold winters
Avg
−8°C in January, 21°C in July
Joliet
Population 148k
Warm summers, cold winters
Avg
−5°C in January, 24°C in July
Naperville
Population 147k
Warm summers, cold winters
Avg
−5°C in January, 24°C in July
Peoria
Population 115k
Hot summers, cold winters
Avg
−3°C in January, 25°C in July
Climate types in Illinois:Dfa
Hot-summer humid continentalCfa
Humid subtropicalDfb
Warm-summer humid continental
Find a city in Illinois
Search 128 cities by name.
A ↑ A–Z
B ↑ A–Z
BartlettBataviaBellevilleBelvidereBerwynBloomingdaleBloomingtonBlue IslandBolingbrookBuffalo GroveBurbank
C ↑ A–Z
CairoCalumet CityCarbondaleCarol StreamCarpentersvilleChampaignCharlestonChicagoChicago HeightsCiceroCollinsvilleCrest HillCrystal Lake
D ↑ A–Z
E ↑ A–Z
East MolineEast PeoriaEast Saint LouisEdwardsvilleElginElk Grove VillageElmhurstElmwood ParkEvanston
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