Illiopolis Weather Forecast

    • 65
    • 85

    Areas Smoke

    • 74
    • 88

    Chance Thunderstorms

    • 66
    • 89

    Slight Chance Thunderstorms

    • 57
    • 79

    Mostly Sunny

    • 60
    • 80

    Partly Sunny

    • 63
    • 80

    Chance Rain Showers

    • 66
    • 85

    Mostly Sunny

Today 19 Jul Sangamon

Sunny. Patchy smoke. Near steady temperature in the mid 80s. Northeast Winds 5 to 10 Mph.

Tonight 19 Jul Sangamon

Partly cloudy. Areas of smoke this Evening, then patchy smoke after midnight. Lows in the mid 60s. East Winds around 5 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Illiopolis Temperature Statistics

July Temperature

Decatur Airport (19.3 miles)

  • Lowest 13 July, 2026

    62.7 °F

  • Average July

    78.7 °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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