With a population of around 1,100, Thomasboro sits in Illinois, United States. The city operates in the Central Time Zone.
In 2025, Thomasboro recorded an average annual temperature of 53°F — about 0.7°F above the 30-year normal of 52°F. The hottest day reached 91°F in July; the coldest was -6°F in December. Total precipitation was 30 inches (drier than usual). The wettest month was April.
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