Harrisburg, PA 17129 Frost Dates
When can you plant in Harrisburg, PA?
The last spring frost here typically falls around 04/09, about 224 days from today. The first fall frost typically arrives around 11/01, about 205 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 Harrisburg, not a forecast for this year.
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.
The actual range around Harrisburg's last frost
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
Harrisburg's growing season runs about 205 days, ranking 16,174 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 124 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.