O'Neill Lake Weather Forecast

    • 61
    • 80

    Mostly Cloudy

    • 62
    • 82

    Partly Sunny

    • 65
    • 85

    Mostly Sunny

    • 66
    • 86

    Mostly Sunny

    • 66
    • 88

    Mostly Sunny

    • 66
    • 92

    Partly Sunny

Today 21 Sep San Diego County Inland Valleys

Mostly cloudy this morning. Becoming mostly sunny. Patchy fog this morning. Highs 77 to 82. Light Winds becoming west 10 Mph this afternoon.

Tonight 21 Sep San Diego County Inland Valleys

Partly cloudy. Patchy fog overnight. Lows 52 to 61. Areas of Winds west to 10 Mph in the evening becoming light.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

O'Neill Lake Temperature Statistics

September Temperature

Oceanside, Camp Pendleton, Marine Corps Air Station (2.5 miles)

  • Lowest 3 September, 2026

    55 °F

  • Average September

    74.7 °F

  • Highest 9 September, 2026

    105.1 °F

Climate (2021–2026)

Oceanside, Camp Pendleton, Marine Corps Air Station (2.5 miles)

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  • Average Low 2021–2026

    54.3 °F

  • Average 2021–2026

    64.2 °F

  • Average High 2021–2026

    74 °F
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