About Fairmont, IL's Climate & Weather History

Fairmont, in Illinois, United States, is home to roughly 2,500 people in the Central Time Zone at 41.6°N latitude.

In 2025, Fairmont recorded an average annual temperature of 51°F — about 1.1°F below the 30-year normal of 52°F. The hottest day reached 93°F in June; the coldest was -9°F in February. Total precipitation was 35 inches (near normal). The wettest month was July.