Arnold, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Arnold, a city in Allegheny County, Pennsylvania.
Overnight
51°F
Mostly Clear
Mostly clear, with a low around 51. Southeast wind around 1 mph.
7-day forecast for Arnold
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 51°F | Mostly Clear | 1 mph SE | 1% |
| Wednesday | 79°F | Partly Sunny | 2 to 9 mph S | 8% |
| Wednesday Night | 60°F | Light Rain | 9 mph S | 93% |
| Thursday | 71°F | Chance Light Rain then Partly Sunny | 7 to 14 mph SW | 45% |
| Thursday Night | 46°F | Partly Cloudy | 1 to 6 mph SW | 1% |
| Friday | 64°F | Partly Sunny then Slight Chance Light Rain | 2 to 8 mph SW | 20% |
| Friday Night | 41°F | Chance Light Rain | 3 to 8 mph W | 35% |
| Saturday | 54°F | Chance Light Rain | 9 to 14 mph W | 33% |
| Saturday Night | 35°F | Chance Light Rain | 6 to 12 mph W | 26% |
| Sunday | 56°F | Partly Sunny | 7 to 15 mph W | 8% |
| Sunday Night | 32°F | Partly Cloudy | 7 to 10 mph W | 6% |
| Monday | 57°F | Mostly Sunny | 8 to 15 mph W | 13% |
| Monday Night | 33°F | Partly Cloudy | 6 to 10 mph SW | 13% |
| Tuesday | 61°F | Mostly Sunny | 10 to 16 mph SW | 4% |
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 Nov 4, 2026.