South Mountain Reservoir Weather Forecast

    • 49
    • 81

    Sunny

    • 50
    • 83

    Sunny

    • 54
    • 84

    Partly Sunny

    • 49
    • 75

    Mostly Cloudy

    • 46
    • 74

    Partly Sunny

    • 46
    • 76

    Mostly Sunny

Today 16 Sep Modoc County

Sunny. Highs in the lower to mid 80s. East Winds 5 to 10 Mph shifting to the south this afternoon.

Tonight 16 Sep Modoc County

Clear. Lows in the mid 40s to lower 50s. South Winds around 5 Mph shifting to the southeast well after midnight.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

South Mountain Reservoir Temperature Statistics

September Temperature

Alturas (22.4 miles)

  • Lowest 13 September, 2025

    41 °F

  • Average September

    66.3 °F

  • Highest 1 September, 2025

    91 °F

Climate (2020–Present)

Alturas (22.4 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    33 °F

  • Average 2020–2025

    49.1 °F

  • Average High 2020–2025

    64.4 °F
Get WillyWeather+ to remove ads