Summerville Weather Forecast

    • 41
    • 77

    Becoming Sunny

    • 44
    • 77

    Partly Sunny

    • 49
    • 85

    Partly Sunny

    • 38
    • 66

    Rain Showers Likely

    • 38
    • 63

    Mostly Cloudy

    • 37
    • 65

    Slight Chance Rain Showers

    • 39
    • 66

    Partly Sunny

Today 22 Sep Grande Ronde Valley

Partly cloudy. Highs in the upper 70s. Northwest wind 5 to 10 Mph.

Tonight 22 Sep Grande Ronde Valley

Mostly clear. Lows in the lower to mid 40s. Northwest wind 5 to 10 Mph in the Evening, becoming light.

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Summerville Temperature Statistics

September Temperature

La Grande/Union County Airport (13 miles)

  • Lowest 15 September, 2026

    36 °F

  • Average September

    58.9 °F

  • Highest 10 September, 2026

    89.1 °F

Climate (2021–2026)

La Grande/Union County Airport (13 miles)

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  • Average Low 2021–2026

    38.3 °F

  • Average 2021–2026

    50.5 °F

  • Average High 2021–2026

    62.7 °F
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