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

Briefing for Heat, Severe Storm, and Flash Flood Risks through Thursday

Dangerously hot and humid conditions are expected through Wednesday. There is also a threat of isolated severe thunderstorms on Wednesday. Flash flooding from locally heavy rainfall is possible on Thursday. See this briefing for details on these hazards. Read More >

Hazardous Weather Conditions

Current conditions at

Trenton-Mercer Airport (KTTN)

Lat: 40.28°NLon: 74.82°WElev: 210ft.

Fair

78°F

26°C

Humidity 76%
Wind Speed Calm
Barometer 29.96 in (1013.7 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 31 Jul 2:53 am EDT
Extended Forecast for

Plainsboro NJ

Flood Watch July 31, 02:00pm until August 1, 06:00am
Click here for hazard details and duration
Flood Watch

  • Overnight

    Overnight: Partly cloudy, with a low around 73. Calm wind.

    Low: 73 °F

    Partly Cloudy

  • Thursday

    Thursday: A chance of showers and thunderstorms before 3pm, then showers likely and possibly a thunderstorm between 3pm and 5pm, then showers and thunderstorms likely after 5pm. Some of the storms could produce heavy rainfall. Partly sunny, with a high near 86. Calm wind becoming east around 5 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between 1 and 2 inches possible.

    High: 86 °F

    Chance
    T-storms then
    Heavy Rain

  • Thursday Night

    Thursday Night: Showers and thunderstorms likely, then showers and possibly a thunderstorm after 8pm. Some of the storms could produce heavy rainfall. Low around 64. Northeast wind around 5 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.

    Low: 64 °F

    Heavy Rain

  • Friday

    Friday: Showers and possibly a thunderstorm, mainly before 2pm, then a chance of showers and thunderstorms after 2pm. High near 71. Northeast wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    High: 71 °F

    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms before 8pm, then a slight chance of showers between 8pm and 2am. Partly cloudy, with a low around 59. North wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 59 °F

    Chance
    Showers

  • Saturday

    Saturday: Sunny, with a high near 80.

    High: 80 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 57.

    Low: 57 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 83.

    High: 83 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 60.

    Low: 60 °F

    Partly Cloudy

Detailed Forecast

Overnight
Partly cloudy, with a low around 73. Calm wind.
Thursday
A chance of showers and thunderstorms before 3pm, then showers likely and possibly a thunderstorm between 3pm and 5pm, then showers and thunderstorms likely after 5pm. Some of the storms could produce heavy rainfall. Partly sunny, with a high near 86. Calm wind becoming east around 5 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between 1 and 2 inches possible.
Thursday Night
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 8pm. Some of the storms could produce heavy rainfall. Low around 64. Northeast wind around 5 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Friday
Showers and possibly a thunderstorm, mainly before 2pm, then a chance of showers and thunderstorms after 2pm. High near 71. Northeast wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Friday Night
A chance of showers and thunderstorms before 8pm, then a slight chance of showers between 8pm and 2am. Partly cloudy, with a low around 59. North wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
Sunny, with a high near 80.
Saturday Night
Mostly clear, with a low around 57.
Sunday
Sunny, with a high near 83.
Sunday Night
Partly cloudy, with a low around 60.
Monday
Mostly sunny, with a high near 85.
Monday Night
Partly cloudy, with a low around 61.
Tuesday
Partly sunny, with a high near 84.
Tuesday Night
Mostly cloudy, with a low around 64.
Wednesday
Partly sunny, with a high near 81.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Plainsboro NJ
 40.34°N 74.59°W (Elev. 89 ft)
Last Update:
4:12 pm EDT Jul 30, 2025
Forecast Valid:
3am EDT Jul 31, 2025-6pm EDT Aug 6, 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