Holtsville Weather Forecast

    • 62
    • 71

    Rain Showers Likely

    • 62
    • 76

    Chance Rain Showers

    • 56
    • 80

    Mostly Sunny

    • 55
    • 70

    Mostly Sunny

    • 56
    • 71

    Partly Sunny

    • 60
    • 74

    Partly Sunny

Today 17 Sep Southwest Suffolk

Cloudy. A chance of Showers this Morning, then Showers likely with isolated Thunderstorms this afternoon. Highs in the lower 70s. East Winds 15 to 20 Mph. Chance of rain 70 percent.

Tonight 17 Sep Southwest Suffolk

Mostly cloudy. Showers likely with isolated Thunderstorms in the Evening, then a chance of Showers with isolated Thunderstorms after midnight. Lows in the lower 60s. Northeast Winds 10 to 15 Mph. Gusts up to 25 Mph in the evening. Chance of rain 70 percent.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Holtsville Temperature Statistics

September Temperature

Islip, Long Island Mac Arthur Airport (3.1 miles)

  • Lowest 9 September, 2025

    54 °F

  • Average September

    69.1 °F

  • Highest 6 September, 2025

    81 °F

Climate (2020–Present)

Islip, Long Island Mac Arthur Airport (3.1 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    47.4 °F

  • Average 2020–2025

    55.2 °F

  • Average High 2020–2025

    63.1 °F
Get WillyWeather+ to remove ads