New Castle Northwest, PA Weather & Growing Conditions
This Afternoon
76°F
Slight Chance Rain Showers
A slight chance of rain showers before 2pm. Partly sunny, with a high near 76. Southeast wind around 5 mph. Chance of precipitation is 20%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 76°F | Slight Chance Rain Showers | 5 mph SE | 17% |
| Tonight | 62°F | Showers And Thunderstorms Likely | 3 mph SE | 69% |
| Sunday | 75°F | Showers And Thunderstorms | 5 to 8 mph W | 96% |
| Sunday Night | 51°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 8 mph NE | 25% |
| Monday | 67°F | Mostly Cloudy | 9 mph NE | 12% |
| Monday Night | 50°F | Chance Rain Showers | 7 to 10 mph NE | 36% |
| Tuesday | 62°F | Chance Rain Showers | 10 to 14 mph E | 45% |
| Tuesday Night | 49°F | Rain Showers Likely | 15 mph E | 71% |
| Wednesday | 62°F | Showers And Thunderstorms Likely | 15 mph E | 71% |
| Wednesday Night | 49°F | Chance Rain Showers | 10 to 14 mph E | 51% |
| Thursday | 65°F | Chance Rain Showers | 8 to 12 mph E | 51% |
| Thursday Night | 49°F | Slight Chance Rain Showers then Mostly Cloudy | 3 to 7 mph E | 15% |
| Friday | 69°F | Partly Sunny | 7 mph NE | 13% |
| Friday Night | 48°F | Partly Cloudy | 2 to 7 mph N | 12% |
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 Sep 19, 2026.