Illiopolis Weather Forecast

    • 60
    • 74

    Chance Thunderstorms

    • 55
    • 74

    Partly Sunny

    • 59
    • 78

    Mostly Sunny

    • 64
    • 80

    Chance Thunderstorms

    • 60
    • 81

    Slight Chance Thunderstorms

    • 65
    • 80

    Chance Thunderstorms

    • 70
    • 83

    Chance Thunderstorms

Today 21 Jun Sangamon

Showers with a chance of Thunderstorms. Locally heavy rainfall possible. Highs in the lower 70s. South Winds around 15 Mph with Gusts up to 25 Mph. Chance of rain near 100 percent.

Tonight 21 Jun Sangamon

Cloudy. A chance of Showers and Thunderstorms this evening. Lows around 60. Southwest Winds 10 to 15 Mph, becoming northwest after midnight. Chance of rain 50 percent.

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Illiopolis Temperature Statistics

June Temperature

Decatur Airport (19.3 miles)

  • Lowest 3 June, 2026

    51.7 °F

  • Average June

    72.6 °F

  • Highest 10 June, 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

    55.5 °F

  • Average High 2021–2026

    65.6 °F
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