Illiopolis Weather Forecast

    • 75
    • 88

    Slight Chance Thunderstorms

    • 75
    • 93

    Increasing Clouds

    • 63
    • 86

    Mostly Sunny

    • 64
    • 84

    Sunny

    • 67
    • 86

    Partly Sunny

    • 67
    • 82

    Chance Rain Showers

    • 66
    • 84

    Chance Rain Showers

Today 26 Jul Sangamon

Partly sunny with a slight chance of Showers and Thunderstorms. Warmer. Near steady temperature in the lower 90s. West Winds around 5 Mph. Chance of rain 20 percent. Heat index Values up to 114.

Tonight 26 Jul Sangamon

Partly cloudy. Lows in the mid 70s. South Winds around 5 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Illiopolis Temperature Statistics

July Temperature

Decatur Airport (19.3 miles)

  • Lowest 23 July, 2026

    51.7 °F

  • Average July

    77 °F

  • Highest 2 July, 2026

    93.7 °F

Climate (2021–2026)

Decatur Airport (19.3 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    45.3 °F

  • Average 2021–2026

    55.5 °F

  • Average High 2021–2026

    65.6 °F
Get WillyWeather+ to remove ads