October weather forecast and climate
Illinois, USA

October is mild and colorful in Illinois as fall foliage is at its peak in the entire state. The average high temperatures are in the beautiful range of 60°F (15.6°C) to 70°F (21.1°C), while the average low temperatures are in the mild 40°F (4.4°C) to 50°F (10°C) zone. Rockford in the north averages between 41°F (5°C) to 63°F (17.2°C), while Mount Vernon in the south is between 44°F (6.7°C) to 67°F (19.4°C).
The fall foliage is at its peak throughout Illinois by the third week of October. The atmosphere is perfect for scenic hikes in the Shawnee National Forest in southern Illinois with breathtaking nature views along the trails. Fall is the time to harvest the abundant supply of fresh apples with their aroma filling the orchards. Pumpkin patches and corn mazes rule the roost. Great River Road offers terrific views of the Mississippi River during the autumn season as it runs through miles of woodlands.
Expect the conditions to steadily become colder with each passing day in October in Illinois.