Upper Oso Reservoir Weather Forecast

    • 70
    • 90

    Slight Chance Rain Showers

    • 72
    • 92

    Partly Sunny

    • 71
    • 95

    Mostly Sunny

Today 7 Sep Orange County Inland

Partly cloudy with a slight chance of Showers and Thunderstorms. Warmer. Highs 89 to 93. Light Winds becoming west 10 Mph this afternoon. Chance of measurable precipitation 20 percent.

Tonight 7 Sep Orange County Inland

Mostly clear in the evening. Becoming partly cloudy. Lows 68 to 72. Areas of Winds west to 10 Mph in the evening becoming light.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Upper Oso Reservoir Temperature Statistics

September Temperature

John Wayne-Orange County Airport (13.7 miles)

  • Lowest 5 September, 2026

    64.9 °F

  • Average September

    73.4 °F

  • Highest 5 September, 2026

    84 °F

Climate (2021–2026)

John Wayne-Orange County Airport (13.7 miles)

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

  • Average Low 2021–2026

    59 °F

  • Average 2021–2026

    66.1 °F

  • Average High 2021–2026

    73.8 °F
Get WillyWeather+ to remove ads