Alton Weather Forecast

    • 73
    • 93

    Chance Thunderstorms

    • 71
    • 89

    Chance Thunderstorms

    • 69
    • 87

    Chance Rain Showers

    • 70
    • 88

    Partly Sunny

    • 72
    • 91

    Slight Chance Thunderstorms

    • 73
    • 93

    Chance Thunderstorms

Today 4 Jul Madison

Sunny in the Morning, then becoming partly sunny. A chance of Showers and Thunderstorms. Humid with Highs in the lower 90s. Southwest Winds around 5 Mph. Chance of rain 50 percent. Heat index Values up to 105.

Tonight 4 Jul Madison

Mostly clear with a slight chance of Showers and Thunderstorms. Near steady temperature in the upper 70s. South Winds around 5 Mph. Chance of rain 20 percent.

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  • Temperature Real-Time

Alton Temperature Statistics

July Temperature

St. Louis Regional Airport (8.1 miles)

  • Lowest 1 July, 2026

    73.8 °F

  • Average July

    82.5 °F

  • Highest 1 July, 2026

    91.4 °F

Climate (2021–2026)

St. Louis Regional Airport (8.1 miles)

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  • Average Low 2021–2026

    46.6 °F

  • Average 2021–2026

    54.5 °F

  • Average High 2021–2026

    66.7 °F
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