Arnold, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Arnold, a city in Allegheny County, Pennsylvania.
Tonight
51°F
Mostly Clear
Mostly clear, with a low around 51. Southeast wind around 2 mph.
7-day forecast for Arnold
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 51°F | Mostly Clear | 2 mph SE | 2% |
| Wednesday | 79°F | Partly Sunny | 2 to 9 mph SE | 7% |
| Wednesday Night | 61°F | Light Rain | 9 mph S | 97% |
| Thursday | 72°F | Chance Light Rain | 7 to 14 mph SW | 45% |
| Thursday Night | 48°F | Partly Cloudy | 0 to 6 mph SW | 4% |
| Friday | 67°F | Partly Sunny | 1 to 7 mph W | 11% |
| Friday Night | 44°F | Chance Light Rain | 2 to 6 mph NW | 28% |
| Saturday | 57°F | Chance Light Rain | 6 to 13 mph W | 30% |
| Saturday Night | 36°F | Slight Chance Light Rain then Mostly Cloudy | 3 to 9 mph W | 24% |
| Sunday | 57°F | Partly Sunny then Slight Chance Light Rain | 3 to 12 mph SW | 17% |
| Sunday Night | 35°F | Slight Chance Light Rain | 10 mph W | 21% |
| Monday | 58°F | Chance Light Rain | 10 to 17 mph W | 31% |
| Monday Night | 36°F | Chance Light Rain then Partly Cloudy | 8 to 13 mph SW | 31% |
| Tuesday | 61°F | Mostly Sunny | 13 to 18 mph SW | 10% |
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.