Harman US

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

WhenTempForecastWindPrecip
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.