New Castle Northwest, PA Weather & Growing Conditions
Tonight
54°F
Mostly Clear
Mostly clear, with a low around 54. Southeast wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 54°F | Mostly Clear | 6 mph SE | 3% |
| Wednesday | 75°F | Mostly Cloudy then Chance Light Rain | 6 to 10 mph S | 25% |
| Wednesday Night | 58°F | Light Rain | 7 to 12 mph S | 100% |
| Thursday | 68°F | Slight Chance Light Rain then Mostly Sunny | 6 to 12 mph SW | 16% |
| Thursday Night | 45°F | Partly Cloudy | 0 to 5 mph SW | 2% |
| Friday | 63°F | Partly Sunny then Slight Chance Light Rain | 0 to 6 mph W | 15% |
| Friday Night | 42°F | Chance Light Rain | 5 mph NW | 29% |
| Saturday | 54°F | Chance Light Rain | 5 to 10 mph W | 32% |
| Saturday Night | 34°F | Chance Light Rain then Mostly Cloudy | 2 to 6 mph W | 32% |
| Sunday | 55°F | Partly Sunny then Slight Chance Light Rain | 2 to 9 mph W | 18% |
| Sunday Night | 33°F | Slight Chance Light Rain | 6 mph W | 20% |
| Monday | 56°F | Chance Light Rain | 6 to 12 mph W | 30% |
| Monday Night | 35°F | Chance Light Rain then Partly Cloudy | 5 to 8 mph SW | 30% |
| Tuesday | 59°F | Mostly Sunny | 8 to 14 mph SW | 11% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for New Castle Northwest, PA
Last spring frost
Apr 30
First fall frost
Oct 23
Growing season
175 days
Hardiness zone
6a
Explore more for New Castle Northwest, PA: full frost dates · planting calendar · Pennsylvania frost dates
Climate data from the nearest NOAA station, New Castle 1 N, Pa (2.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.