Illiopolis Weather Forecast

    • 66
    • 83

    Chance Thunderstorms

    • 63
    • 82

    Mostly Cloudy

    • 64
    • 84

    Mostly Sunny

    • 68
    • 86

    Mostly Sunny

    • 70
    • 88

    Rain Showers Likely

    • 66
    • 84

    Chance Thunderstorms

    • 65
    • 85

    Slight Chance Rain Showers

Today 5 Jul Sangamon

Partly sunny with a chance of Showers and Thunderstorms. Near steady temperature in the lower 80s. North Winds 5 to 10 Mph. Chance of rain 40 percent.

Tonight 5 Jul Sangamon

Partly cloudy. A chance of Showers and Thunderstorms this evening. Lows in the mid 60s. North Winds 5 to 10 Mph. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Illiopolis Temperature Statistics

July Temperature

Decatur Airport (19.3 miles)

  • Lowest 1 July, 2026

    75.7 °F

  • Average July

    84.1 °F

  • Highest 2 July, 2026

    93.7 °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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