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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

WhenTempForecastWindPrecip
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

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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.