South Mountain Reservoir Weather Forecast

    • 59
    • 84

    Slight Chance Thunderstorms

    • 52
    • 86

    Mostly Sunny

    • 51
    • 86

    Sunny

    • 51
    • 87

    Sunny

    • 50
    • 85

    Mostly Sunny

    • 50
    • 85

    Mostly Sunny

    • 49
    • 85

    Sunny

Today 21 Jul Modoc County

Mostly cloudy. Slight chance of Showers early this Morning, then slight chance of Thunderstorms in the late morning and afternoon. Patchy smoke late this morning. Highs in the lower to mid 80s. East Winds 5 to 10 Mph shifting to the north late this afternoon. Chance of precipitation 20 percent.

Tonight 21 Jul Modoc County

Mostly cloudy with a 10 percent chance of Thunderstorms until well after Midnight, then mostly clear well after midnight. Lows in the lower to mid 60s. Northwest Winds 5 to 10 Mph shifting to the southwest late this Evening, then shifting to the southeast after midnight.

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South Mountain Reservoir Temperature Statistics

July Temperature

Alturas (22.4 miles)

  • Lowest 1 July, 2026

    38.6 °F

  • Average July

    69.3 °F

  • Highest 11 July, 2026

    95.6 °F

Climate (2021–2026)

Alturas (22.4 miles)

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  • Average Low 2021–2026

    33.4 °F

  • Average 2021–2026

    49.3 °F

  • Average High 2021–2026

    64.7 °F
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