New Castle, DE Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for New Castle, a city in New Castle County, Delaware.
This Afternoon
83°F
Mostly Sunny
Mostly sunny, with a high near 83. North wind around 10 mph.
7-day forecast for New Castle
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 83°F | Mostly Sunny | 10 mph N | 0% |
| Tonight | 64°F | Partly Cloudy | 5 to 10 mph N | 3% |
| Saturday | 76°F | Mostly Sunny | 5 to 10 mph E | 2% |
| Saturday Night | 65°F | Mostly Cloudy then Patchy Fog | 5 to 10 mph E | 10% |
| Sunday | 79°F | Showers And Thunderstorms Likely | 5 to 10 mph SE | 63% |
| Sunday Night | 65°F | Showers And Thunderstorms | 5 to 10 mph W | 83% |
| Monday | 72°F | Chance Rain Showers | 10 mph NE | 45% |
| Monday Night | 63°F | Chance Rain Showers | 10 to 15 mph NE | 34% |
| Tuesday | 66°F | Chance Rain Showers | 10 to 15 mph NE | 37% |
| Tuesday Night | 59°F | Chance Rain Showers | 15 mph NE | 37% |
| Wednesday | 64°F | Chance Rain Showers | 10 to 15 mph NE | 38% |
| Wednesday Night | 58°F | Chance Showers And Thunderstorms | 15 mph NE | 36% |
| Thursday | 65°F | Chance Showers And Thunderstorms | 10 to 15 mph NE | 34% |
| Thursday Night | 58°F | Chance Showers And Thunderstorms | 10 mph NE | 34% |
Forecast source: National Weather Service (api.weather.gov) for New Castle (39.670, -75.567). Updated through the day.
Growing snapshot for New Castle
Last spring frost
Apr 7
First fall frost
Nov 1
Growing season
209 days
Hardiness zone
7b
More local growing data for New Castle: nearby ZIP 19720 weather · frost dates · planting calendar · Delaware frost dates
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Climate data from the nearest NOAA station, Wilmington New Castle Co Ap, De (1.9 mi from New Castle). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.