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

Trenton-Mercer Airport (KTTN)

Lat: 40.28°NLon: 74.82°WElev: 210ft.

Fair

24°C

75°F

Humidity 84%
Wind Speed SE 15 km/h
Barometer 1017.4 mb (30.07 in)
Dewpoint 21°C (70°F)
Visibility 16 km
Last update 12 Jul 9:53 pm EDT
Extended Forecast for

Princeton NJ

  • Tonight

    Tonight: Patchy fog after midnight. Otherwise, mostly cloudy, with a low around 21. Calm wind.

    Low: 21 °C

    Mostly Cloudy
    then Patchy
    Fog

  • Sunday

    Sunday: Cloudy, then gradually becoming mostly sunny, with a high near 30. East wind 5 to 10 km/h.

    High: 30 °C

    Decreasing
    Clouds

  • Sunday Night

    Sunday Night: A slight chance of showers and thunderstorms before 2am, then a chance of showers between 2am and 5am, then a chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 21. South wind 5 to 10 km/h. Chance of precipitation is 40%. New rainfall amounts of less than 1 mm, except higher amounts possible in thunderstorms.

    Low: 21 °C

    Slight Chance
    T-storms then
    Chance
    Showers

  • Monday

    Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 31. Calm wind. Chance of precipitation is 70%. New rainfall amounts between 2.5 and 5 mm possible.

    High: 31 °C

    Chance
    Showers then
    Showers
    Likely

  • Monday Night

    Monday Night: Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Mostly cloudy, with a low around 21. Calm wind. Chance of precipitation is 60%. New rainfall amounts between 2.5 and 5 mm possible.

    Low: 21 °C

    Showers
    Likely then
    Chance
    Showers

  • Tuesday

    Tuesday: A slight chance of showers after 2pm. Mostly sunny, with a high near 33. Chance of precipitation is 20%.

    High: 33 °C

    Mostly Sunny
    then Slight
    Chance
    Showers

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 22.

    Low: 22 °C

    Partly Cloudy

  • Wednesday

    Wednesday: A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 33. Chance of precipitation is 30%.

    High: 33 °C

    Mostly Sunny
    then Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 23. Chance of precipitation is 30%.

    Low: 23 °C

    Chance
    T-storms then
    Chance
    Showers

Detailed Forecast

Tonight
Patchy fog after midnight. Otherwise, mostly cloudy, with a low around 21. Calm wind.
Sunday
Cloudy, then gradually becoming mostly sunny, with a high near 30. East wind 5 to 10 km/h.
Sunday Night
A slight chance of showers and thunderstorms before 2am, then a chance of showers between 2am and 5am, then a chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 21. South wind 5 to 10 km/h. Chance of precipitation is 40%. New rainfall amounts of less than 1 mm, except higher amounts possible in thunderstorms.
Monday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 31. Calm wind. Chance of precipitation is 70%. New rainfall amounts between 2.5 and 5 mm possible.
Monday Night
Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Mostly cloudy, with a low around 21. Calm wind. Chance of precipitation is 60%. New rainfall amounts between 2.5 and 5 mm possible.
Tuesday
A slight chance of showers after 2pm. Mostly sunny, with a high near 33. Chance of precipitation is 20%.
Tuesday Night
Partly cloudy, with a low around 22.
Wednesday
A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 33. Chance of precipitation is 30%.
Wednesday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 23. Chance of precipitation is 30%.
Thursday
A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 33. Chance of precipitation is 50%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 24. Chance of precipitation is 40%.
Friday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 33. Chance of precipitation is 60%.
Friday Night
Showers and thunderstorms likely. Mostly cloudy, with a low around 22. Chance of precipitation is 60%.
Saturday
A chance of showers and thunderstorms. Partly sunny, with a high near 31. Chance of precipitation is 40%.
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ABOUT THIS FORECAST

 
Point Forecast:
Princeton NJ
 40.35°N 74.67°W (Elev. 190 m)
Last Update:
4:12 pm EDT Jul 12, 2025
Forecast Valid:
10pm EDT Jul 12, 2025-6pm EDT Jul 19, 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