Mount Gretna, PA 17015 Frost Dates
When can you plant in Mount Gretna, PA?
Typically, the last spring freeze lands around 04/20, roughly 235 days out. The first fall frost typically arrives around 10/25, about 185 frost-free days later.
Zone 7a (0 to 5°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 Mount Gretna, not a forecast for this year.
What to do before the first frost
About 8 weeks of growing season left in Mount Gretna before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/20 is the middle of 30 years of NOAA records, not a promise. Plant by 04/05 and you're betting against frost in roughly 9 years out of 10. 05/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mount Gretna compares
About 185 days separate Mount Gretna's last and first frost, putting it 23,344 of 40,283 ZIP codes nationally. Within PA, it ranks 744 of 2,088.
Learn more
the frost range covers how to read the range around Mount Gretna's dates instead of trusting one. local microclimates covers what one yard in Mount Gretna can differ from the 17015 normal.