Mount Vernon Weather Forecast

    • 56
    • 89

    Increasing Clouds

    • 55
    • 87

    Partly Sunny

    • 54
    • 84

    Partly Sunny

    • 47
    • 75

    Mostly Sunny

    • 52
    • 80

    Mostly Sunny

    • 54
    • 86

    Partly Sunny

Today 18 Sep John Day Basin

Sunny. Highs in the 80s. Light wind.

Tonight 18 Sep John Day Basin

Mostly cloudy. Lows in the lower to mid 50s. Northwest wind 5 to 10 Mph in the Evening, becoming light.

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Mount Vernon Temperature Statistics

September Temperature

Grant County Regional Airport (6.8 miles)

  • Lowest 15 September, 2025

    41.9 °F

  • Average September

    67.5 °F

  • Highest 2 September, 2025

    95.9 °F

Climate (2020–Present)

Grant County Regional Airport (6.8 miles)

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  • Average Low 2020–2025

    39.1 °F

  • Average 2020–2025

    50.4 °F

  • Average High 2020–2025

    62.2 °F
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