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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 45–59°F. Annual precipitation ranges 32.3–50.3 in 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
24°F in January, 77°F in July
Aurora
Population 201k
Warm summers, cold winters
Avg
23°F in January, 74°F in July
Rockford
Population 148k
Warm summers, very cold winters
Avg
18°F in January, 70°F in July
Joliet
Population 148k
Warm summers, cold winters
Avg
24°F in January, 75°F in July
Naperville
Population 147k
Warm summers, cold winters
Avg
23°F in January, 74°F in July
Peoria
Population 115k
Hot summers, cold winters
Avg
26°F in January, 76°F 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
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East MolineEast PeoriaEast Saint LouisEdwardsvilleElginElk Grove VillageElmhurstElmwood ParkEvanston
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