Mercersburg, PA Weather & Growing Conditions
This Afternoon
76°F
Mostly Cloudy
Mostly cloudy, with a high near 76. East wind around 3 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 76°F | Mostly Cloudy | 3 mph E | 10% |
| Tonight | 64°F | Chance Rain Showers | 3 to 9 mph SE | 41% |
| Sunday | 78°F | Chance Showers And Thunderstorms | 3 to 9 mph S | 86% |
| Sunday Night | 58°F | Showers And Thunderstorms | 2 to 10 mph NW | 86% |
| Monday | 67°F | Chance Rain Showers | 6 to 10 mph NE | 33% |
| Monday Night | 53°F | Rain Showers Likely | 5 to 8 mph NE | 61% |
| Tuesday | 60°F | Rain Showers Likely | 8 mph NE | 70% |
| Tuesday Night | 50°F | Rain Showers Likely | 7 to 10 mph NE | 61% |
| Wednesday | 59°F | Rain Showers Likely | 10 mph NE | 56% |
| Wednesday Night | 51°F | Chance Rain Showers | 7 to 10 mph NE | 45% |
| Thursday | 61°F | Chance Rain Showers | 6 to 10 mph NE | 45% |
| Thursday Night | 50°F | Chance Rain Showers | 8 mph N | 40% |
| Friday | 67°F | Slight Chance Rain Showers | 8 mph N | 23% |
| Friday Night | 50°F | Slight Chance Rain Showers | 5 to 8 mph N | 17% |
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 Sep 19, 2026.