South Mountain Reservoir Weather Forecast

    • 40
    • 65

    Mostly Sunny

    • 43
    • 70

    Mostly Sunny

    • 46
    • 75

    Partly Sunny

    • 43
    • 72

    Mostly Sunny

    • 43
    • 70

    Mostly Sunny

    • 43
    • 74

    Mostly Sunny

    • 38
    • 67

    Mostly Sunny

Today 31 May Modoc County

Sunny. Highs in the mid 60s to lower 70s. North Winds 5 to 10 Mph.

Tonight 31 May Modoc County

Mostly clear. Lows in the lower to mid 40s. North Winds 5 to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

South Mountain Reservoir Temperature Statistics

May Temperature

Alturas (22.4 miles)

  • Lowest 19 May, 2026

    27.6 °F

  • Average May

    55.6 °F

  • Highest 12 May, 2026

    88.6 °F

Climate (2021–Present)

Alturas (22.4 miles)

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  • Average Low 2021–2026

    33.5 °F

  • Average 2021–2026

    49.6 °F

  • Average High 2021–2026

    65 °F
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