With a population of around 11,400, Summit sits in Illinois, United States. The city operates in the Central Time Zone.
In 2025, Summit recorded an average annual temperature of 51°F — about 0.9°F below the 30-year normal of 52°F. The hottest day reached 96°F in August; the coldest was -8°F in February. Total precipitation was 38 inches (wetter than usual). The wettest month was June.
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