Merrimac Weather Forecast

    • 60
    • 88

    Partly Sunny

    • 57
    • 81

    Mostly Sunny

    • 53
    • 78

    Partly Sunny

    • 52
    • 79

    Mostly Sunny

    • 55
    • 81

    Mostly Sunny

    • 58
    • 81

    Partly Sunny

Today 23 Aug Monroe

Mostly sunny. Highs in the upper 80s. Northwest Winds around 5 Mph.

Tonight 23 Aug Monroe

Mostly clear. Patchy fog. Lows in the lower 60s. Light and variable Winds.

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Merrimac Temperature Statistics

August Temperature

St. Louis Downtown Airport (16.2 miles)

  • Lowest 3 August, 2025

    56.6 °F

  • Average August

    80.3 °F

  • Highest 16 August, 2025

    98.7 °F

Climate (2020–Present)

St. Louis Downtown Airport (16.2 miles)

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  • Average Low 2020–2025

    47.4 °F

  • Average 2020–2025

    57.8 °F

  • Average High 2020–2025

    68.5 °F
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