Lake Saint John Weather Forecast

    • 62
    • 86

    Chance Thunderstorms

    • 61
    • 74

    Rain Showers

    • 59
    • 71

    Rain Showers Likely

    • 57
    • 69

    Chance Thunderstorms

    • 57
    • 72

    Slight Chance Rain Showers

    • 58
    • 76

    Partly Sunny

Today 16 Sep Hamlin

Mostly sunny. Highs in the mid 80s. South Winds 5 to 10 Mph, becoming southwest this afternoon.

Tonight 16 Sep Hamlin

Mostly cloudy. A slight chance of Thunderstorms in the Evening, then a chance of Thunderstorms after midnight. Lows in the lower 60s. Northeast Winds around 5 Mph. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Lake Saint John Temperature Statistics

September Temperature

Watertown, Watertown Municipal Airport (23 miles)

  • Lowest 7 September, 2025

    37.9 °F

  • Average September

    61.8 °F

  • Highest 11 September, 2025

    81 °F

Climate (2020–Present)

Watertown, Watertown Municipal Airport (23 miles)

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  • Average Low 2020–2025

    35 °F

  • Average 2020–2025

    45.2 °F

  • Average High 2020–2025

    55.6 °F
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