Chicago, Illinois weather in October

Averages from 2021–2025 (155 days of record).

Average high: 64°F
Average low: 50°F
Rainy days: ~11 per month
Total precipitation: 4.4 in
Warmest recorded: 87°F
Coldest recorded: 28°F

Expect October days in Chicago, Illinois to top out around 64°F and cool to about 50°F overnight, with roughly 11 days of measurable rain across the month. In recent years October has ranged from 28°F to 87°F.

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Current Chicago, Illinois forecast → · Historical data by Open-Meteo (ERA5).