National Weather Service Forecast for: New Castle DE
Issued by: National Weather Service Philadelphia, PA
Updated: 4:09 pm EDT Sep 12, 2026
 
Tonight

Tonight: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2am. Low around 71. Southeast wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Showers

 Sunday

Sunday: Showers and thunderstorms before noon, then a slight chance of thunderstorms between noon and 1pm. Patchy fog before 7am. High near 84. Southwest wind around 5 mph becoming northwest in the afternoon. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Showers and
Patchy Fog
then Mostly
Sunny
 Sunday
Night
Sunday Night: Increasing clouds, with a low around 70. West wind around 5 mph.
Increasing
Clouds

 Monday

Monday: Mostly sunny, with a high near 76. North wind 10 to 15 mph.
Mostly Sunny

 Monday
Night
Monday Night: Mostly clear, with a low around 57. North wind 5 to 10 mph.
Mostly Clear

 Tuesday

Tuesday: Sunny, with a high near 77.
Sunny

 Tuesday
Night
Tuesday Night: Mostly clear, with a low around 60.
Mostly Clear

 Wednesday

Wednesday: Sunny, with a high near 80.
Sunny

 Wednesday
Night
Wednesday Night: Mostly clear, with a low around 64.
Mostly Clear
Lo 71 °F Hi 84 °F Lo 70 °F Hi 76 °F Lo 57 °F Hi 77 °F Lo 60 °F Hi 80 °F Lo 64 °F

Flood Watch
 

Tonight
 
 A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2am. Low around 71. Southeast wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Sunday
 
 Showers and thunderstorms before noon, then a slight chance of thunderstorms between noon and 1pm. Patchy fog before 7am. High near 84. Southwest wind around 5 mph becoming northwest in the afternoon. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Sunday Night
 
 Increasing clouds, with a low around 70. West wind around 5 mph.
Monday
 
 Mostly sunny, with a high near 76. North wind 10 to 15 mph.
Monday Night
 
 Mostly clear, with a low around 57. North wind 5 to 10 mph.
Tuesday
 
 Sunny, with a high near 77.
Tuesday Night
 
 Mostly clear, with a low around 60.
Wednesday
 
 Sunny, with a high near 80.
Wednesday Night
 
 Mostly clear, with a low around 64.
Thursday
 
 Sunny, with a high near 83.
Thursday Night
 
 Mostly clear, with a low around 67.
Friday
 
 A chance of showers. Mostly sunny, with a high near 83. Chance of precipitation is 30%.
Friday Night
 
 A chance of showers. Mostly cloudy, with a low around 66. Chance of precipitation is 30%.
Saturday
 
 A chance of showers. Partly sunny, with a high near 80. Chance of precipitation is 30%.

 

Forecast from NOAA-NWS for New Castle DE.