Winthrop Harbor, in Illinois, United States, is home to roughly 6,800 people in the Central Time Zone at 42.5°N latitude.
In 2025, Winthrop Harbor recorded an average annual temperature of 49°F — about 0.7°F above the 30-year normal of 48°F. The hottest day reached 96°F in June; the coldest was -10°F in February. Total precipitation was 31 inches (drier than usual). The wettest month was June.
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