Illiopolis Weather Forecast

    • 42
    • 72

    Partly Sunny

    • 42
    • 73

    Mostly Sunny

    • 46
    • 76

    Sunny

    • 48
    • 77

    Sunny

    • 48
    • 76

    Mostly Sunny

    • 52
    • 77

    Partly Sunny

Today 19 Oct Sangamon

Sunny. Highs in the lower 70s. South Winds around 5 Mph.

Tonight 19 Oct Sangamon

Partly cloudy. Lows in the lower 40s. Light and variable Winds.

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Illiopolis Temperature Statistics

October Temperature

Decatur Airport (19.3 miles)

  • Lowest 17 October, 2026

    37 °F

  • Average October

    64.5 °F

  • Highest 13 October, 2026

    90.6 °F

Climate (2021–2026)

Decatur Airport (19.3 miles)

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  • Average Low 2021–2026

    45.3 °F

  • Average 2021–2026

    55.6 °F

  • Average High 2021–2026

    65.7 °F
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