Mount Vernon Weather Forecast

    • 61
    • 87

    Increasing Clouds

    • 61
    • 84

    Mostly Sunny

    • 62
    • 85

    Sunny

    • 63
    • 89

    Sunny

    • 65
    • 91

    Mostly Sunny

    • 63
    • 89

    Mostly Sunny

    • 63
    • 87

    Mostly Sunny

Today 15 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy with patchy fog this morning. Becoming sunny. Highs 83 to 88. Areas of Winds south to 10 Mph becoming southwest with Gusts to 25 Mph this afternoon.

Tonight 15 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy this evening. Becoming mostly cloudy. Lows 52 to 60. Areas of Winds southwest 10 Mph this evening becoming light.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Mount Vernon Temperature Statistics

September Temperature

San Bernardino Intl. Airport (4.3 miles)

  • Lowest 2 September, 2026

    59 °F

  • Average September

    76.9 °F

  • Highest 9 September, 2026

    105.8 °F

Climate (2021–2026)

San Bernardino Intl. Airport (4.3 miles)

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

  • Average Low 2021–2026

    54.2 °F

  • Average 2021–2026

    63.2 °F

  • Average High 2021–2026

    80.3 °F
Get WillyWeather+ to remove ads