Mercersburg, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mercersburg, a borough in Franklin County, Pennsylvania.
This Afternoon
77°F
Slight Chance Rain Showers
A slight chance of rain showers. Partly sunny, with a high near 77. Southeast wind around 3 mph. Chance of precipitation is 20%.
7-day forecast for Mercersburg
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 77°F | Slight Chance Rain Showers | 3 mph SE | 15% |
| Tonight | 65°F | Chance Rain Showers | 2 to 9 mph SE | 45% |
| Sunday | 82°F | Rain Showers | 5 to 9 mph S | 88% |
| Sunday Night | 58°F | Showers And Thunderstorms then Chance Showers And Thunderstorms | 2 to 9 mph NW | 81% |
| Monday | 70°F | Chance Rain Showers | 9 mph NE | 40% |
| Monday Night | 55°F | Rain Showers Likely | 7 mph NE | 68% |
| Tuesday | 63°F | Showers And Thunderstorms Likely | 8 mph NE | 74% |
| Tuesday Night | 52°F | Rain Showers Likely | 9 mph NE | 73% |
| Wednesday | 58°F | Rain Showers Likely | 9 mph NE | 57% |
| Wednesday Night | 51°F | Chance Rain Showers | 7 to 10 mph NE | 39% |
| Thursday | 61°F | Chance Rain Showers | 7 to 10 mph NE | 28% |
| Thursday Night | 50°F | Slight Chance Rain Showers | 7 mph NE | 24% |
| Friday | 67°F | Chance Rain Showers | 8 mph N | 25% |
| Friday Night | 51°F | Chance Rain Showers | 8 mph N | 25% |
Forecast source: National Weather Service (api.weather.gov) for Mercersburg (39.832, -77.903). Updated through the day.
Growing snapshot for Mercersburg
Last spring frost
Apr 7
First fall frost
Nov 4
Growing season
209 days
Hardiness zone
7a
More local growing data for Mercersburg: nearby ZIP 17236 weather · frost dates · planting calendar · Pennsylvania frost dates
Nearby towns & communities
Blue Ridge Summit
Chambersburg
Fayetteville
Fort Loudon
Greencastle
Guilford
Marion
Mont Alto
Orrstown
Pen Mar
Rouzerville
Scotland
State Line
Wayne Heights
Waynesboro
Climate data from the nearest NOAA station, Hagerstown Washington Co Ap, Md (13.2 mi from Mercersburg). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.