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
70°F
Mostly Sunny
Mostly sunny, with a high near 70. South wind around 5 mph.
7-day forecast for New Castle
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 70°F | Mostly Sunny | 5 mph S | 1% |
| Tonight | 53°F | Mostly Clear | 5 mph S | 2% |
| Wednesday | 74°F | Patchy Fog then Sunny | 5 to 10 mph S | 5% |
| Wednesday Night | 61°F | Mostly Cloudy | 5 mph S | 5% |
| Thursday | 74°F | Chance Light Rain | 5 to 10 mph S | 37% |
| Thursday Night | 64°F | Light Rain | 5 mph S | 83% |
| Friday | 69°F | Light Rain | 0 to 5 mph W | 83% |
| Friday Night | 55°F | Light Rain | 5 mph NW | 77% |
| Saturday | 66°F | Chance Light Rain then Mostly Sunny | 5 to 10 mph NW | 28% |
| Saturday Night | 46°F | Partly Cloudy | 10 mph NW | 14% |
| Sunday | 61°F | Mostly Sunny | 5 mph NW | 6% |
| Sunday Night | 45°F | Slight Chance Light Rain | 5 to 10 mph W | 19% |
| Monday | 61°F | Slight Chance Light Rain | 10 mph W | 22% |
| Monday Night | 43°F | Slight Chance Light Rain | 10 mph W | 21% |
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 Nov 4, 2026.