Port Royal, PA 17037 Frost Dates
When can you plant in Port Royal, PA?
Typically, the last spring freeze lands around 04/21, roughly 236 days out. The first fall frost typically arrives around 10/24, about 185 frost-free days later.
Zone 6b (-5 to 0°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Port Royal, not a forecast for this year.
What to do before the first frost
About 8 weeks of growing season left in Port Royal before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/21 isn't a guarantee
04/21 is the middle of 30 years of NOAA records, not a promise. Plant by 04/06 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Port Royal compares
About 185 days separate Port Royal's last and first frost, putting it 23,250 of 40,283 ZIP codes nationally. Within PA, it ranks 720 of 2,088.
Learn more
the frost range covers how to read the range around Port Royal's dates instead of trusting one. local microclimates covers what one yard in Port Royal can differ from the 17037 normal.