Macungie, PA 18106 Frost Dates
Frost dates for Macungie, PA, ZIP 18106
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.
The USDA Plant Hardiness Zone Map puts Macungie 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
Zone 7a around Macungie 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 Macungie compares
About 184 days separate Macungie's last and first frost, putting it 23,540 of 40,283 ZIP codes nationally. Within PA, it ranks 792 of 2,088.
Learn more
local microclimates explains what one yard in Macungie can differ from the 18106 normal, and zone vs. frost date explains why Zone 7a and Macungie's frost date answer different questions.