Ottawa Weather Forecast

    • 64
    • 83

    Partly Sunny

    • 68
    • 85

    Partly Sunny

    • 67
    • 79

    Rain Showers

    • 63
    • 78

    Chance Thunderstorms

    • 65
    • 83

    Partly Sunny

    • 69
    • 85

    Slight Chance Thunderstorms

    • 71
    • 87

    Slight Chance Thunderstorms

Today 3 Aug La Salle

Mostly sunny. Temperatures in the lower 80s. Light and variable Winds.

Tonight 3 Aug La Salle

Clear. Lows in the mid 60s. Southeast Winds around 5 Mph.

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Ottawa Temperature Statistics

August Temperature

Illinois Valley Regional Airport (15.5 miles)

  • Lowest 1 August, 2026

    66.2 °F

  • Average August

    69.2 °F

  • Highest 1 August, 2026

    69.8 °F

Climate (2021–2026)

Illinois Valley Regional Airport (15.5 miles)

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  • Average Low 2021–2026

    43.3 °F

  • Average 2021–2026

    52.9 °F

  • Average High 2021–2026

    62.6 °F
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