Harrisburg, PA 17107 Frost Dates
When can you plant in Harrisburg, PA?
Around 04/09 is the usual last spring frost, about 224 days away. The first fall frost typically arrives around 11/01, about 205 frost-free days later.
The USDA Plant Hardiness Zone Map puts Harrisburg in Zone 7a (0 to 5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's 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.
Why 04/09 isn't a guarantee
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 16,165 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 115 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.