Alton Weather Forecast

    • 57
    • 71

    Patchy Fog

    • 59
    • 73

    Decreasing Clouds

    • 56
    • 73

    Partly Sunny

    • 53
    • 69

    Mostly Cloudy

    • 52
    • 68

    Mostly Cloudy

    • 52
    • 68

    Mostly Cloudy

    • 52
    • 67

    Mostly Cloudy

Today 20 Jul Northern Coastal Humboldt

Mostly cloudy. Slight chance of rain Showers in the morning. Highs 63 to 78. West wind around 10 Mph.

Tonight 20 Jul Northern Coastal Humboldt

Mostly cloudy. Patchy fog through the night. Lows 50 to 60. Northwest wind around 5 Mph.

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Alton Temperature Statistics

July Temperature

Fortuna Rohnerville Airport (0.6 miles)

  • Lowest 1 July, 2026

    50 °F

  • Average July

    54.9 °F

  • Highest 4 July, 2026

    66.2 °F

Climate (2021–2026)

Fortuna Rohnerville Airport (0.6 miles)

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  • Average Low 2021–2026

    45.3 °F

  • Average 2021–2026

    51.4 °F

  • Average High 2021–2026

    59.7 °F
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