Grand Lake St. Marys SPB Weather Forecast

    • 61
    • 76

    Rain Showers Likely

    • 66
    • 83

    Slight Chance Thunderstorms

    • 70
    • 88

    Chance Thunderstorms

    • 65
    • 86

    Rain Showers

    • 50
    • 73

    Chance Rain Showers

    • 50
    • 66

    Partly Sunny

Today 16 May Mercer

Partly cloudy with a chance of Showers and Thunderstorms this Morning, then mostly cloudy with Showers likely with a chance of Thunderstorms this afternoon. Highs in the upper 70s. Southwest Winds 15 to 20 Mph. Chance of rain 70 percent.

Tonight 16 May Mercer

Partly cloudy. A chance of Showers and Thunderstorms, mainly in the evening. Lows around 60. Southwest Winds 10 to 15 Mph, Diminishing to around 5 Mph after midnight. Chance of rain 40 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Grand Lake St. Marys SPB Temperature Statistics

May Temperature

Versailles Darke County Airport (23 miles)

  • Lowest 2 May, 2026

    33.8 °F

  • Average May

    53.7 °F

  • Highest 4 May, 2026

    73.4 °F

Climate (2021–Present)

Versailles Darke County Airport (23 miles)

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  • Average Low 2021–2026

    43.3 °F

  • Average 2021–2026

    52.5 °F

  • Average High 2021–2026

    61.7 °F
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