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.
Today
85°F
Partly Sunny
Partly sunny, with a high near 85. East wind around 5 mph.
7-day forecast for New Castle
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 85°F | Partly Sunny | 5 mph E | 0% |
| Tonight | 70°F | Mostly Cloudy | 0 to 5 mph E | 12% |
| Wednesday | 84°F | Showers And Thunderstorms Likely | 5 mph SE | 78% |
| Wednesday Night | 75°F | Chance Showers And Thunderstorms | 5 mph S | 56% |
| Thursday | 88°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 19% |
| Thursday Night | 76°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 23% |
| Friday | 89°F | Mostly Sunny then Chance Showers And Thunderstorms | 5 mph SW | 32% |
| Friday Night | 74°F | Chance Showers And Thunderstorms | 5 mph SW | 44% |
| Saturday | 87°F | Partly Sunny then Chance Showers And Thunderstorms | 5 mph SW | 36% |
| Saturday Night | 73°F | Chance Showers And Thunderstorms | 5 mph SW | 36% |
| Sunday | 88°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 mph W | 17% |
| Sunday Night | 74°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 mph SW | 17% |
| Monday | 89°F | Sunny | 5 to 10 mph W | 11% |
| Monday Night | 74°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph W | 15% |
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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Wilmington
Wilmington Manor
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 Aug 4, 2026.