Mercer Weather Forecast

    • 57
    • 81

    Chance Rain Showers

    • 47
    • 66

    Rain Showers

    • 51
    • 77

    Chance Rain Showers

    • 44
    • 67

    Partly Sunny

    • 42
    • 66

    Mostly Sunny

    • 43
    • 68

    Partly Sunny

    • 49
    • 73

    Mostly Cloudy

Today 3 Sep Mercer

Mostly sunny. Near steady temperature in the upper 70s. Southwest Winds around 10 Mph.

Tonight 3 Sep Mercer

Mainly clear this Evening, then becoming mostly cloudy. A chance of Showers with a slight chance of Thunderstorms after midnight. Lows in the upper 50s. South Winds 5 to 10 Mph. Chance of rain 40 percent.

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Mercer Temperature Statistics

September Temperature

New Castle, New Castle Municipal Airport (16.2 miles)

  • Lowest 1 September, 2025

    46 °F

  • Average September

    61.6 °F

  • Highest 1 September, 2025

    78.1 °F

Climate (2020–Present)

New Castle, New Castle Municipal Airport (16.2 miles)

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  • Average Low 2020–2025

    42 °F

  • Average 2020–2025

    51.4 °F

  • Average High 2020–2025

    61.1 °F
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