Karns City, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Karns City, a borough in Butler County, Pennsylvania.
This Afternoon
77°F
Sunny
Sunny. High near 77, with temperatures falling to around 71 in the afternoon. South wind around 6 mph.
7-day forecast for Karns City
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 77°F | Sunny | 6 mph S | 1% |
| Tonight | 51°F | Mostly Clear | 5 mph SE | 3% |
| Wednesday | 75°F | Partly Sunny | 3 to 8 mph SE | 8% |
| Wednesday Night | 59°F | Light Rain | 6 to 9 mph S | 99% |
| Thursday | 69°F | Chance Light Rain | 6 to 10 mph SW | 28% |
| Thursday Night | 46°F | Partly Cloudy | 1 to 5 mph SW | 3% |
| Friday | 64°F | Partly Sunny | 1 to 6 mph W | 13% |
| Friday Night | 42°F | Chance Light Rain | 2 to 6 mph NW | 31% |
| Saturday | 54°F | Chance Light Rain | 6 to 9 mph W | 31% |
| Saturday Night | 35°F | Chance Light Rain then Mostly Cloudy | 6 mph W | 30% |
| Sunday | 54°F | Partly Sunny then Slight Chance Light Rain | 3 to 9 mph SW | 18% |
| Sunday Night | 33°F | Slight Chance Light Rain | 5 to 8 mph W | 23% |
| Monday | 55°F | Chance Light Rain | 8 to 12 mph W | 33% |
| Monday Night | 34°F | Chance Light Rain | 6 to 9 mph SW | 33% |
Forecast source: National Weather Service (api.weather.gov) for Karns City (40.997, -79.726). Updated through the day.
Growing snapshot for Karns City
Last spring frost
May 7
First fall frost
Oct 14
Growing season
159 days
Hardiness zone
6a
More local growing data for Karns City: nearby ZIP 16041 weather · frost dates · planting calendar · Pennsylvania frost dates
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Climate data from the nearest NOAA station, Butler 2 Sw, Pa (15.6 mi from Karns City). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.