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

Areas of Excessive Rainfall; Watching for Tropical Cyclone Development in the Atlantic

Heavy to excessive rainfall Wednesday may bring areas of flash and urban flooding over portions of the Ohio and Tennessee Valleys. In Arizona and New Mexico, heavy to excessive rainfall from monsoon thunderstorms may bring isolated flash and urban flooding Thursday into Saturday. Two tropical waves in the Atlantic are being monitored for tropical cyclone formation within the next few days. Read More >

Current conditions at

Trenton-Mercer Airport (KTTN)

Lat: 40.28°NLon: 74.82°WElev: 210ft.

Partly Cloudy

74°F

23°C

Humidity 74%
Wind Speed S 6 mph
Barometer 29.98 in (1014.7 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Last update 23 Sep 9:53 pm EDT
Extended Forecast for

Princeton Junction NJ

  • Tonight

    Tonight: A chance of showers and thunderstorms before 2am, then a slight chance of showers between 2am and 5am. Mostly cloudy, with a low around 63. Calm wind. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 63 °F

    Chance
    Showers

  • Wednesday

    Wednesday: A chance of showers and thunderstorms, mainly between 4pm and 5pm. Mostly cloudy, with a high near 82. Calm wind. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 82 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2am. Low around 65. Calm wind. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 65 °F

    Chance
    Showers then
    Showers

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 77. South wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    High: 77 °F

    Showers

  • Thursday Night

    Thursday Night: Showers and possibly a thunderstorm before 11pm, then showers likely. Low around 64. South wind around 5 mph becoming calm. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 64 °F

    Showers

  • Friday

    Friday: A chance of showers. Mostly cloudy, with a high near 79. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

    High: 79 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers. Mostly cloudy, with a low around 60. Chance of precipitation is 30%.

    Low: 60 °F

    Chance
    Showers

  • Saturday

    Saturday: A chance of showers after 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 30%.

    High: 79 °F

    Mostly Cloudy
    then Chance
    Showers

  • Saturday Night

    Saturday Night: A chance of showers before 2am. Mostly cloudy, with a low around 60. Chance of precipitation is 30%.

    Low: 60 °F

    Chance
    Showers

Detailed Forecast

Tonight
A chance of showers and thunderstorms before 2am, then a slight chance of showers between 2am and 5am. Mostly cloudy, with a low around 63. Calm wind. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday
A chance of showers and thunderstorms, mainly between 4pm and 5pm. Mostly cloudy, with a high near 82. Calm wind. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2am. Low around 65. Calm wind. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Thursday
Showers and possibly a thunderstorm. High near 77. South wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Thursday Night
Showers and possibly a thunderstorm before 11pm, then showers likely. Low around 64. South wind around 5 mph becoming calm. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Friday
A chance of showers. Mostly cloudy, with a high near 79. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Friday Night
A chance of showers. Mostly cloudy, with a low around 60. Chance of precipitation is 30%.
Saturday
A chance of showers after 2pm. Mostly cloudy, with a high near 79. Chance of precipitation is 30%.
Saturday Night
A chance of showers before 2am. Mostly cloudy, with a low around 60. Chance of precipitation is 30%.
Sunday
Mostly sunny, with a high near 80.
Sunday Night
Partly cloudy, with a low around 57.
Monday
Mostly sunny, with a high near 78.
Monday Night
Mostly cloudy, with a low around 56.
Tuesday
Mostly sunny, with a high near 75.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Princeton Junction NJ
 40.32°N 74.62°W (Elev. 85 ft)
Last Update:
4:09 pm EDT Sep 23, 2025
Forecast Valid:
11pm EDT Sep 23, 2025-6pm EDT Sep 30, 2025
 
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