With a population of around 42,500, Plainfield sits in Illinois, United States. The city operates in the Central Time Zone.
In 2025, Plainfield recorded an average annual temperature of 51°F — about 1.8°F above the 30-year normal of 49°F. The hottest day reached 93°F in May; the coldest was -9°F in February. Total precipitation was 34 inches (near normal). The wettest month was July.
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