Alton Weather Forecast

    • 54
    • 68

    Increasing Clouds

    • 54
    • 67

    Increasing Clouds

    • 52
    • 66

    Patchy Fog

    • 54
    • 66

    Mostly Cloudy

    • 55
    • 70

    Mostly Cloudy

    • 54
    • 70

    Mostly Cloudy

    • 53
    • 68

    Mostly Cloudy

Today 19 Aug Northern Coastal Humboldt

Mostly cloudy until early afternoon then becoming partly cloudy. Patchy fog in the morning. Highs 62 to 76. Northwest wind around 10 Mph.

Tonight 19 Aug Northern Coastal Humboldt

Mostly cloudy. Patchy fog. Lows 48 to 58. Northwest wind around 10 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Alton Temperature Statistics

August Temperature

Fortuna Rohnerville Airport (0.6 miles)

  • Lowest 3 August, 2026

    48.2 °F

  • Average August

    57.3 °F

  • Highest 1 August, 2026

    71.6 °F

Climate (2021–2026)

Fortuna Rohnerville Airport (0.6 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    45.3 °F

  • Average 2021–2026

    51.4 °F

  • Average High 2021–2026

    59.7 °F
Get WillyWeather+ to remove ads