San Marcos Weather Forecast

    • 62
    • 78

    Increasing Clouds

    • 63
    • 80

    Mostly Sunny

    • 64
    • 82

    Mostly Sunny

    • 67
    • 83

    Mostly Sunny

    • 69
    • 86

    Mostly Sunny

    • 69
    • 88

    Partly Sunny

Today 17 Aug San Diego County Inland Valleys

Partly cloudy this morning. Becoming mostly sunny. Highs 77 to 81 in the western Valleys to 82 to 87 near the Foothills. Light Winds becoming west 10 Mph this afternoon.

Tonight 17 Aug San Diego County Inland Valleys

Mostly clear in the evening. Becoming partly cloudy overnight with patchy fog. Lows 56 to 61. Areas of Winds west to 10 Mph in the evening becoming light.

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San Marcos Temperature Statistics

August Temperature

Carlsbad, McClellan-Palomar Airport (6.2 miles)

  • Lowest 2 August, 2025

    62.7 °F

  • Average August

    68.8 °F

  • Highest 7 August, 2025

    79.6 °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

    62.5 °F

  • Average High 2020–2025

    68.9 °F
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