National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Selinsgrove Penn Valley Airport (KSEG)

Lat: 40.82°NLon: 76.87°WElev: 443ft.

Mostly Cloudy

63°F

17°C

Humidity 97%
Wind Speed Calm
Barometer 30.13 in (1020.0 mb)
Dewpoint 62°F (17°C)
Visibility 9.00 mi
Last update 16 Aug 1:53 am EDT
Extended Forecast for

Northumberland PA

  • Overnight

    Overnight: Mostly cloudy, with a low around 65. Calm wind.

    Low: 65 °F

    Mostly Cloudy

  • Sunday

    Sunday: Showers and possibly a thunderstorm. High near 75. Calm wind becoming south 5 to 8 mph in the morning. Winds could gust as high as 21 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.

    High: 75 °F

    Showers
    Likely then
    Showers

  • Sunday Night

    Sunday Night: Showers and possibly a thunderstorm before 2am, then a slight chance of showers between 2am and 3am. Low around 67. South wind around 6 mph becoming calm after midnight. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 67 °F

    Showers

  • Monday

    Monday: A chance of showers and thunderstorms, mainly between 2pm and 5pm. Partly sunny, with a high near 84. Calm wind becoming northwest around 6 mph in the afternoon. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 84 °F

    Partly Sunny
    then Chance
    Showers

  • Monday Night

    Monday Night: Partly cloudy, with a low around 63. Calm wind.

    Low: 63 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 82.

    High: 82 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 61.

    Low: 61 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.

    Low: 63 °F

    Chance
    Showers

Detailed Forecast

Overnight
Mostly cloudy, with a low around 65. Calm wind.
Sunday
Showers and possibly a thunderstorm. High near 75. Calm wind becoming south 5 to 8 mph in the morning. Winds could gust as high as 21 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Sunday Night
Showers and possibly a thunderstorm before 2am, then a slight chance of showers between 2am and 3am. Low around 67. South wind around 6 mph becoming calm after midnight. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Monday
A chance of showers and thunderstorms, mainly between 2pm and 5pm. Partly sunny, with a high near 84. Calm wind becoming northwest around 6 mph in the afternoon. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Monday Night
Partly cloudy, with a low around 63. Calm wind.
Tuesday
Sunny, with a high near 82.
Tuesday Night
Mostly clear, with a low around 61.
Wednesday
Mostly sunny, with a high near 84.
Wednesday Night
A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.
Thursday
Mostly sunny, with a high near 79.
Thursday Night
Partly cloudy, with a low around 57.
Friday
Mostly sunny, with a high near 79.
Friday Night
Mostly cloudy, with a low around 60.
Saturday
A chance of showers. Partly sunny, with a high near 79. Chance of precipitation is 40%.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Northumberland PA
 40.89°N 76.82°W (Elev. 545 ft)
Last Update:
2:05 am EDT Aug 16, 2026
Forecast Valid:
2am EDT Aug 16, 2026-6pm EDT Aug 22, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation