Charleston is a city of approximately 21,200 people in Illinois, United States. Located in the Central Time Zone at 39.5°N latitude.
In 2025, Charleston recorded an average annual temperature of 54°F — about 0.7°F above the 30-year normal of 53°F. The hottest day reached 92°F in August; the coldest was -5°F in December. Total precipitation was 32 inches (drier than usual). The wettest month was April.
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