Ontario Weather Forecast

    • 32
    • 39

    Rain

    • 13
    • 46

    Rain

    • 24
    • 32

    Partly Sunny

    • 20
    • 46

    Partly Sunny

    • 22
    • 34

    Partly Sunny

    • 32
    • 38

    Mostly Cloudy

Today 17 Dec Knox

Partly sunny. Highs in the upper 30s. North Winds around 5 Mph, becoming southeast this afternoon.

Tonight 17 Dec Knox

Mostly cloudy. Rain likely after midnight. Breezy with Lows in the lower 30s. Temperature rising into the lower 40s after midnight. South Winds 15 to 25 Mph with Gusts up to 35 Mph. Chance of rain 70 percent.

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Ontario Temperature Statistics

December Temperature

Galesburg Municipal Airport (11.8 miles)

  • Lowest 14 December, 2025

    -12.5 °F

  • Average December

    19.5 °F

  • Highest 9 December, 2025

    41.2 °F

Climate (2020–Present)

Galesburg Municipal Airport (11.8 miles)

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  • Average Low 2020–2025

    41.3 °F

  • Average 2020–2025

    51.5 °F

  • Average High 2020–2025

    61.7 °F
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