Fullerton Weather Forecast

    • 64
    • 84

    Patchy Fog

    • 62
    • 83

    Partly Sunny

    • 61
    • 80

    Patchy Fog

    • 61
    • 81

    Mostly Sunny

    • 62
    • 84

    Sunny

    • 64
    • 89

    Sunny

Today 13 Sep Los Angeles County San Gabriel Valley

Low Clouds and fog in the morning then sunny. Highs in the mid 80s to around 90.

Tonight 13 Sep Los Angeles County San Gabriel Valley

Clear except for patchy low Clouds and fog after midnight. Lows in the lower to mid 60s.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Fullerton Temperature Statistics

September Temperature

Fullerton, Fullerton Municipal Airport (6.2 miles)

  • Lowest 2 September, 2026

    63.6 °F

  • Average September

    79.2 °F

  • Highest 9 September, 2026

    108 °F

Climate (2021–2026)

Fullerton, Fullerton Municipal Airport (6.2 miles)

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

  • Average Low 2021–2026

    57.1 °F

  • Average 2021–2026

    66.6 °F

  • Average High 2021–2026

    76.9 °F
Get WillyWeather+ to remove ads