Waterloo Weather Forecast

    • 57
    • 82

    Slight Chance Thunderstorms

    • 47
    • 74

    Sunny

    • 55
    • 74

    Chance Thunderstorms

    • 63
    • 85

    Slight Chance Thunderstorms

    • 67
    • 88

    Slight Chance Thunderstorms

    • 69
    • 89

    Chance Rain Showers

Today 12 May Monroe

Sunny. Highs in the lower 80s. Southwest Winds 5 to 10 Mph.

Tonight 12 May Monroe

Mostly clear in the Evening, then becoming partly cloudy. A slight chance of Showers and Thunderstorms. Lows in the upper 50s. Southwest Winds 5 to 10 Mph, becoming west after midnight. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Waterloo Temperature Statistics

May Temperature

St. Louis Downtown Airport (15.5 miles)

  • Lowest 7 May, 2026

    39.7 °F

  • Average May

    59.8 °F

  • Highest 9 May, 2026

    81.6 °F

Climate (2021–Present)

St. Louis Downtown Airport (15.5 miles)

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  • Average Low 2021–2026

    47.6 °F

  • Average 2021–2026

    58.4 °F

  • Average High 2021–2026

    69.2 °F
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