Saint Jacob is a city of approximately 1,100 people in Illinois, United States. Located in the Central Time Zone at 38.7°N latitude.
In 2025, Saint Jacob recorded an average annual temperature of 56°F — about 1.7°F below the 30-year normal of 58°F. The hottest day reached 94°F in July; the coldest was 0°F in January. Total precipitation was 41 inches (near normal). Snowfall totaled 7 inches, below the 11-inch average. The wettest month was April.
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