Grand Lake St. Marys SPB Weather Forecast

    • 68
    • 81

    Mostly Sunny

    • 71
    • 86

    Chance Rain Showers

    • 72
    • 89

    Rain Showers Likely

    • 65
    • 84

    Slight Chance Thunderstorms

    • 63
    • 81

    Mostly Sunny

    • 66
    • 82

    Mostly Sunny

Today 25 Jul Mercer

Mostly sunny. Highs in the lower 80s. Light and variable Winds, becoming southwest around 5 Mph this late morning and afternoon.

Tonight 25 Jul Mercer

Mostly clear. Lows in the mid 60s. Southwest Winds around 5 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Grand Lake St. Marys SPB Temperature Statistics

July Temperature

Versailles Darke County Airport (23 miles)

  • Lowest 23 July, 2026

    50 °F

  • Average July

    75.4 °F

  • Highest 3 July, 2026

    93.2 °F

Climate (2021–2026)

Versailles Darke County Airport (23 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    43.3 °F

  • Average 2021–2026

    52.5 °F

  • Average High 2021–2026

    61.8 °F
Get WillyWeather+ to remove ads