About Walnut, IL's Climate & Weather History

With a population of around 1,400, Walnut sits in Illinois, United States. The city operates in the Central Time Zone.

In 2025, Walnut recorded an average annual temperature of 52°F. The hottest temperatures reached 96°F in June; the coolest were -11°F in January. Total precipitation for the year was 32 inches, with the wettest month being July. Snowfall for the year totaled approximately 8 inches.