About Green Rock, IL's Climate & Weather History

With a population of around 3,000, Green Rock sits in Illinois, United States. The city operates in the Central Time Zone.

In 2025, Green Rock recorded an average annual temperature of 52°F — about 2.4°F above the 30-year normal of 50°F. The hottest day reached 97°F in June; the coldest was -11°F in January. Total precipitation was 33 inches (drier than usual). The wettest month was July.