Delavan is a city of approximately 1,600 people in Illinois, United States. Located in the Central Time Zone at 40.4°N latitude.
In 2025, Delavan recorded an average annual temperature of 54°F — about 1.0°F above the 30-year normal of 53°F. The hottest day reached 93°F in September; the coldest was -7°F in January. Total precipitation was 33 inches (drier than usual). Snowfall totaled 8 inches, below the 26-inch average. The wettest month was July.
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