Ontario Weather Forecast

    • 66
    • 79

    Chance Thunderstorms

    • 61
    • 78

    Mostly Cloudy

    • 62
    • 78

    Slight Chance Thunderstorms

    • 65
    • 80

    Chance Rain Showers

    • 61
    • 79

    Mostly Sunny

    • 62
    • 77

    Partly Sunny

Today 18 Aug Knox

Partly sunny. A slight chance of Showers and Thunderstorms this afternoon. Highs around 80. Southwest Winds 5 to 10 Mph. Chance of rain 20 percent.

Tonight 18 Aug Knox

Partly cloudy in the Evening, then becoming mostly cloudy. A chance of Showers. A chance of Thunderstorms, mainly in the evening. Lows in the mid 60s. Southwest Winds 5 to 10 Mph in the Evening, becoming light and variable. Chance of rain 50 percent.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Ontario Temperature Statistics

August Temperature

Galesburg Municipal Airport (11.8 miles)

  • Lowest 3 August, 2026

    57.7 °F

  • Average August

    73.8 °F

  • Highest 10 August, 2026

    88.2 °F

Climate (2021–2026)

Galesburg Municipal Airport (11.8 miles)

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

  • Average Low 2021–2026

    41.8 °F

  • Average 2021–2026

    52.1 °F

  • Average High 2021–2026

    62.5 °F
Get WillyWeather+ to remove ads