Illiopolis Weather Forecast

    • 74
    • 89

    Becoming Sunny

    • 74
    • 93

    Decreasing Clouds

    • 74
    • 94

    Mostly Sunny

    • 75
    • 94

    Mostly Sunny

    • 74
    • 94

    Chance Thunderstorms

    • 73
    • 93

    Slight Chance Thunderstorms

    • 72
    • 93

    Slight Chance Thunderstorms

Today 28 Jun Sangamon

Mostly sunny. Highs around 90. South Winds around 10 Mph with Gusts up to 20 Mph. Heat index Values up to 103.

Tonight 28 Jun Sangamon

Mostly clear this Evening, then becoming partly cloudy. Lows in the mid 70s. South Winds 10 to 15 Mph.

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  • Temperature Real-Time

Illiopolis Temperature Statistics

June Temperature

Decatur Airport (19.3 miles)

  • Lowest 3 June, 2026

    51.7 °F

  • Average June

    71.7 °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

    65.5 °F
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