Mount San Antonio Weather Forecast

    • 58
    • 70

    Sunny

    • 55
    • 67

    Mostly Sunny

    • 52
    • 63

    Sunny

    • 49
    • 62

    Sunny

    • 48
    • 61

    Mostly Sunny

    • 51
    • 63

    Mostly Sunny

    • 55
    • 66

    Mostly Sunny

Today 11 Sep Eastern San Gabriel Mountains

Sunny. Highs from the mid 80s to mid 90s at low Elevations to the 70s at high Elevations. Southwest Winds around 15 Mph in the afternoon.

Tonight 11 Sep Eastern San Gabriel Mountains

Mostly clear. Lows in the 60s to around 70 except the mid to upper 50s Colder Valleys and Slopes.

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Mount San Antonio Temperature Statistics

September Temperature

Brackett Field Airport (14.9 miles)

  • Lowest 2 September, 2026

    60.8 °F

  • Average September

    79.4 °F

  • Highest 9 September, 2026

    105.8 °F

Climate (2021–2026)

Brackett Field Airport (14.9 miles)

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  • Average Low 2021–2026

    56.1 °F

  • Average 2021–2026

    68.1 °F

  • Average High 2021–2026

    76 °F
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