Waterloo Lake Weather Forecast

    • 64
    • 74

    Rain Showers

    • 66
    • 82

    Rain Showers Likely

    • 65
    • 81

    Rain Showers Likely

    • 64
    • 79

    Rain Showers Likely

    • 64
    • 81

    Chance Thunderstorms

    • 68
    • 82

    Chance Thunderstorms

Today 21 May Grayson

Cloudy. A chance of Showers and Thunderstorms in the Morning, then Showers and Thunderstorms likely in the afternoon. Highs in the mid 70s. East Winds 5 to 10 Mph. Chance of rain 70 percent.

Tonight 21 May Grayson

Mostly cloudy with a chance of Showers with a slight chance of Thunderstorms. Lows in the mid 60s. Northeast Winds around 5 Mph. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Waterloo Lake Temperature Statistics

May Temperature

Sherman/Denison, Grayson County Airport (5.6 miles)

  • Lowest 2 May, 2026

    44.6 °F

  • Average May

    68.2 °F

  • Highest 14 May, 2026

    87.8 °F

Climate (2021–Present)

Sherman/Denison, Grayson County Airport (5.6 miles)

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  • Average Low 2021–2026

    55.8 °F

  • Average 2021–2026

    64.6 °F

  • Average High 2021–2026

    77 °F
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