Arnold, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Arnold, a city in Allegheny County, Pennsylvania.
This Afternoon
78°F
Partly Sunny
Partly sunny, with a high near 78. North wind around 8 mph.
7-day forecast for Arnold
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 78°F | Partly Sunny | 8 mph N | 10% |
| Tonight | 57°F | Partly Cloudy | 7 mph NE | 10% |
| Saturday | 80°F | Partly Sunny | 6 mph E | 5% |
| Saturday Night | 65°F | Mostly Cloudy then Showers And Thunderstorms Likely | 6 mph SE | 65% |
| Sunday | 78°F | Showers And Thunderstorms | 6 to 9 mph SW | 96% |
| Sunday Night | 58°F | Showers And Thunderstorms | 9 mph N | 96% |
| Monday | 70°F | Chance Rain Showers | 12 mph NE | 36% |
| Monday Night | 57°F | Showers And Thunderstorms Likely | 13 mph E | 62% |
| Tuesday | 67°F | Showers And Thunderstorms Likely | 15 mph E | 70% |
| Tuesday Night | 54°F | Showers And Thunderstorms Likely | 13 to 16 mph E | 67% |
| Wednesday | 65°F | Showers And Thunderstorms Likely | 15 mph E | 63% |
| Wednesday Night | 53°F | Chance Showers And Thunderstorms | 8 to 15 mph E | 52% |
| Thursday | 67°F | Chance Showers And Thunderstorms | 10 mph E | 41% |
| Thursday Night | 52°F | Slight Chance Rain Showers | 3 to 9 mph NE | 22% |
Forecast source: National Weather Service (api.weather.gov) for Arnold (40.579, -79.765). Updated through the day.
Growing snapshot for Arnold
Last spring frost
Apr 16
First fall frost
Nov 2
Growing season
199 days
Hardiness zone
6b
More local growing data for Arnold: nearby ZIP 15030 weather · frost dates · planting calendar · Pennsylvania frost dates
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Climate data from the nearest NOAA station, Natrona Lock 4, Pa (3.7 mi from Arnold). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.