Cornerstone Weather Forecast

    • 51
    • 75

    Mostly Sunny

    • 53
    • 81

    Mostly Sunny

    • 53
    • 83

    Sunny

    • 53
    • 79

    Mostly Sunny

    • 57
    • 83

    Mostly Sunny

    • 56
    • 89

    Mostly Sunny

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Cornerstone Temperature Statistics

May Temperature

Napa, Napa County Airport (7.5 miles)

  • Lowest 4 May, 2026

    46.7 °F

  • Average May

    60 °F

  • Highest 6 May, 2026

    74.6 °F

Climate (2021–Present)

Napa, Napa County Airport (7.5 miles)

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  • Average Low 2021–2026

    47.3 °F

  • Average 2021–2026

    58.3 °F

  • Average High 2021–2026

    70.2 °F
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