Williamsport Weather Forecast

    • 19
    • 34

    Decreasing Clouds

    • 28
    • 38

    Mostly Cloudy

    • 31
    • 44

    Chance Rain/Snow

    • 29
    • 42

    Mostly Cloudy

    • 35
    • 42

    Chance Rain Showers

    • 32
    • 50

    Slight Chance Rain Showers

Today 21 Dec Southern Lycoming

Mostly sunny. Highs in the mid 30s. Temperature falling into the upper 20s in the afternoon. West Winds 15 to 20 Mph with Gusts up to 30 Mph.

Tonight 21 Dec Southern Lycoming

Partly cloudy. Near steady temperature in the lower 30s. Southwest Winds 5 to 10 Mph with Gusts up to 25 Mph.

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  • Temperature Real-Time

Williamsport Temperature Statistics

December Temperature

Williamsport - Lycoming County Airport (3.7 miles)

  • Lowest 9 December, 2025

    6.1 °F

  • Average December

    26.8 °F

  • Highest 18 December, 2025

    46.9 °F

Climate (2020–Present)

Williamsport - Lycoming County Airport (3.7 miles)

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  • Average Low 2020–2025

    43.8 °F

  • Average 2020–2025

    53 °F

  • Average High 2020–2025

    63.2 °F
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