Mercersburg, PA Weather & Growing Conditions
Today
75°F
Mostly Sunny
Mostly sunny, with a high near 75. South wind 7 to 12 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 75°F | Mostly Sunny | 7 to 12 mph S | 1% |
| Tonight | 61°F | Light Rain | 8 mph SE | 94% |
| Thursday | 76°F | Light Rain Likely | 2 to 8 mph S | 57% |
| Thursday Night | 55°F | Slight Chance Light Rain then Mostly Cloudy | 2 mph W | 18% |
| Friday | 70°F | Slight Chance Light Rain | 0 to 3 mph NW | 17% |
| Friday Night | 47°F | Partly Cloudy | 3 mph NW | 9% |
| Saturday | 59°F | Mostly Sunny | 3 to 12 mph W | 12% |
| Saturday Night | 40°F | Partly Cloudy | 8 mph W | 11% |
| Sunday | 59°F | Mostly Sunny | 7 to 10 mph NW | 4% |
| Sunday Night | 38°F | Mostly Clear | 7 mph W | 3% |
| Monday | 59°F | Sunny | 6 to 13 mph W | 4% |
| Monday Night | 36°F | Mostly Clear | 6 mph W | 3% |
| Tuesday | 64°F | Sunny | 3 to 10 mph W | 1% |
| Tuesday Night | 38°F | Mostly Clear | 5 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Mercersburg, PA
Last spring frost
Apr 7
First fall frost
Nov 4
Growing season
209 days
Hardiness zone
7a
Explore more for Mercersburg, PA: full frost dates · planting calendar · Pennsylvania frost dates
Climate data from the nearest NOAA station, Hagerstown Washington Co Ap, Md (13.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.