Harrisburg, PA 17110 Frost Dates
When can you plant in Harrisburg, PA?
Typically, the last spring freeze lands around 04/09, roughly 224 days out. The first fall frost typically arrives around 11/01, about 205 frost-free days later.
Harrisburg sits in USDA Zone 7a (0 to 5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 9 weeks of growing season left in Harrisburg 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
04/09 is the middle of 30 years of NOAA records, not a promise. Plant by 03/27 and you're betting against frost in roughly 9 years out of 10. 04/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Harrisburg compares
About 205 days separate Harrisburg's last and first frost, putting it 16,166 of 40,283 ZIP codes nationally. Within PA, it ranks 116 of 2,088.
Learn more
zone vs. frost date covers why Zone 7a and Harrisburg's frost date answer different questions. the frost range covers how to read the range around Harrisburg's dates instead of trusting one.