Grantham Weather Forecast

    • 63
    • 73

    Chance Thunderstorms

    • 58
    • 79

    Partly Sunny

    • 66
    • 88

    Rain Showers Likely

    • 63
    • 81

    Rain Showers

    • 60
    • 82

    Mostly Sunny

    • 59
    • 80

    Partly Sunny

Today 28 Jun Sullivan

Cloudy with a chance of Showers. A slight chance of Thunderstorms in the afternoon. Highs in the lower 70s. South Winds around 10 Mph. Chance of rain 40 percent.

Tonight 28 Jun Sullivan

Mostly cloudy with a chance of Showers and Thunderstorms in the Evening, then partly cloudy with a slight chance of Showers after midnight. Humid with Lows in the lower 60s. Light and variable Winds, becoming west around 10 Mph after midnight. Chance of rain 50 percent.

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Grantham Temperature Statistics

June Temperature

Lebanon Municipal Airport (12.4 miles)

  • Lowest 2 June, 2025

    42.7 °F

  • Average June

    68.9 °F

  • Highest 24 June, 2025

    100.7 °F

Climate (2020–Present)

Lebanon Municipal Airport (12.4 miles)

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  • Average Low 2020–2025

    38.3 °F

  • Average 2020–2025

    48.8 °F

  • Average High 2020–2025

    59.8 °F
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