Mercersburg, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mercersburg, a borough in Franklin County, Pennsylvania.
Today
75°F
Patchy Fog then Mostly Sunny
Patchy fog before 8am. Mostly sunny, with a high near 75. South wind 0 to 13 mph, with gusts as high as 21 mph.
7-day forecast for Mercersburg
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 75°F | Patchy Fog then Mostly Sunny | 0 to 13 mph S | 1% |
| Tonight | 61°F | Light Rain | 6 to 9 mph S | 94% |
| Thursday | 76°F | Light Rain Likely | 3 to 9 mph S | 58% |
| Thursday Night | 54°F | Slight Chance Light Rain then Mostly Cloudy | 2 mph W | 19% |
| Friday | 69°F | Slight Chance Light Rain | 2 mph NW | 17% |
| Friday Night | 46°F | Partly Cloudy | 3 mph NW | 10% |
| Saturday | 59°F | Mostly Sunny | 3 to 12 mph W | 12% |
| Saturday Night | 38°F | Partly Cloudy | 6 to 9 mph W | 11% |
| Sunday | 59°F | Mostly Sunny | 7 to 10 mph NW | 4% |
| Sunday Night | 37°F | Mostly Clear | 7 mph W | 3% |
| Monday | 59°F | Sunny | 6 to 13 mph W | 4% |
| Monday Night | 35°F | Mostly Clear | 2 to 6 mph W | 4% |
| Tuesday | 64°F | Sunny | 2 to 10 mph W | 1% |
| Tuesday Night | 36°F | Mostly Clear | 5 mph W | 0% |
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 Nov 4, 2026.