Allentown, PA 18103 Frost Dates
Frost dates for Allentown, PA, ZIP 18103
Typically, the last spring freeze lands around 04/20, roughly 235 days out. The first fall frost typically arrives around 10/24, about 184 frost-free days later.
Allentown 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
Zone 7a around Allentown has about 8 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 04/20 isn't a guarantee
04/20 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. 05/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Allentown compares
About 184 days separate Allentown's last and first frost, putting it 23,387 of 40,283 ZIP codes nationally. Within PA, it ranks 753 of 2,088.
Learn more
the frost range explains how to read the range around Allentown's dates instead of trusting one, and local microclimates explains what one yard in Allentown can differ from the 18103 normal.