Karns City, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Karns City, a borough in Butler County, Pennsylvania.
Overnight
54°F
Mostly Cloudy
Mostly cloudy, with a low around 54. East wind around 5 mph.
7-day forecast for Karns City
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 54°F | Mostly Cloudy | 5 mph E | 1% |
| Saturday | 75°F | Mostly Cloudy | 6 mph E | 3% |
| Saturday Night | 60°F | Showers And Thunderstorms | 6 mph SE | 81% |
| Sunday | 75°F | Showers And Thunderstorms | 8 mph SW | 95% |
| Sunday Night | 50°F | Chance Rain Showers then Mostly Cloudy | 9 mph N | 43% |
| Monday | 67°F | Chance Rain Showers | 9 mph NE | 28% |
| Monday Night | 48°F | Rain Showers Likely | 7 to 12 mph E | 56% |
| Tuesday | 61°F | Rain Showers Likely | 12 mph E | 56% |
| Tuesday Night | 47°F | Rain Showers Likely | 14 mph E | 57% |
| Wednesday | 59°F | Rain Showers Likely | 14 mph E | 57% |
| Wednesday Night | 47°F | Rain Showers Likely | 12 mph E | 62% |
| Thursday | 64°F | Rain Showers Likely then Slight Chance Showers And Thunderstorms | 10 mph E | 62% |
| Thursday Night | 46°F | Slight Chance Showers And Thunderstorms | 7 mph E | 24% |
| Friday | 68°F | Partly Sunny then Slight Chance Rain Showers | 7 mph NE | 15% |
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 Sep 19, 2026.