South Mountain Reservoir Weather Forecast

    • 37
    • 54

    Rain Likely

    • 37
    • 60

    Partly Sunny

    • 41
    • 66

    Sunny

    • 45
    • 73

    Mostly Sunny

    • 47
    • 76

    Partly Sunny

    • 45
    • 75

    Mostly Sunny

Today 29 May Modoc County

Mostly cloudy. Rain early this Morning, then chance of rain in the late morning and afternoon. Highs in the lower to mid 50s. West Winds 5 to 10 Mph. Chance of rain 80 percent.

Tonight 29 May Modoc County

Mostly cloudy with a 10 percent chance of rain in the Evening, then partly cloudy after midnight. Lows in the mid 30s to lower 40s. West 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

    56 °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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