Illiopolis Weather Forecast

    • 74
    • 94

    Isolated Thunderstorms

    • 71
    • 89

    Thunderstorms Likely

    • 72
    • 88

    Chance Thunderstorms

    • 73
    • 91

    Rain Showers Likely

    • 69
    • 87

    Rain Showers Likely

    • 65
    • 85

    Slight Chance Rain Showers

Today 26 Jun Sangamon

Mostly sunny. Isolated Showers and Thunderstorms this afternoon. Highs in the lower 90s. Southwest Winds 5 to 10 Mph. Chance of rain 20 percent. Heat index Values up to 103.

Tonight 26 Jun Sangamon

Partly cloudy with isolated Showers and Thunderstorms. Humid with Lows in the mid 70s. South Winds 5 to 10 Mph. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Illiopolis Temperature Statistics

June Temperature

Decatur Airport (19.3 miles)

  • Lowest 2 June, 2025

    51.7 °F

  • Average June

    75.2 °F

  • Highest 21 June, 2025

    95.6 °F

Climate (2020–Present)

Decatur Airport (19.3 miles)

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  • Average Low 2020–2025

    45.1 °F

  • Average 2020–2025

    55 °F

  • Average High 2020–2025

    64.9 °F
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