San Marcos Weather Forecast

    • 48
    • 69

    Mostly Sunny

    • 49
    • 69

    Mostly Sunny

    • 52
    • 72

    Mostly Sunny

    • 55
    • 76

    Mostly Sunny

    • 55
    • 79

    Mostly Sunny

    • 54
    • 77

    Mostly Sunny

Today 5 Dec San Diego County Inland Valleys

Mostly sunny. Highs 68 to 73. Light Winds.

Tonight 5 Dec San Diego County Inland Valleys

Clear. Lows 41 to 47 in wind Sheltered Areas to 45 to 50 in warmer Locations. Light Winds.

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San Marcos Temperature Statistics

December Temperature

Carlsbad, McClellan-Palomar Airport (6.2 miles)

  • Lowest 2 December, 2025

    48 °F

  • Average December

    56.8 °F

  • Highest 1 December, 2025

    63 °F

Climate (2020–Present)

Carlsbad, McClellan-Palomar Airport (6.2 miles)

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  • Average Low 2020–2025

    56.6 °F

  • Average 2020–2025

    62.4 °F

  • Average High 2020–2025

    68.7 °F
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