Granite City Weather Forecast

    • 73
    • 96

    Thunderstorms

    • 66
    • 79

    Thunderstorms

    • 69
    • 87

    Mostly Sunny

    • 71
    • 93

    Chance Thunderstorms

    • 70
    • 91

    Slight Chance Thunderstorms

    • 70
    • 93

    Chance Thunderstorms

Today 9 Sep Madison

Mostly sunny. A slight chance of Showers in the Morning, then a chance of Showers and Thunderstorms in the afternoon. Hot with Highs in the mid 90s. Southwest Winds 5 to 10 Mph, becoming west in the afternoon. Chance of rain 50 percent. Heat index Values up to 105.

Tonight 9 Sep Madison

Mostly clear and not as cool. Near steady temperature in the mid 70s. South Winds around 5 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Granite City Temperature Statistics

September Temperature

St. Louis Downtown Airport (9.3 miles)

  • Lowest 1 September, 2026

    70.6 °F

  • Average September

    85.9 °F

  • Highest 5 September, 2026

    102.7 °F

Climate (2021–2026)

St. Louis Downtown Airport (9.3 miles)

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  • Average Low 2021–2026

    47.7 °F

  • Average 2021–2026

    58.6 °F

  • Average High 2021–2026

    69.4 °F
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