Prompton, PA 18456 Frost Dates
When can you plant in Prompton, PA?
The last spring frost here typically falls around 05/14, about 259 days from today. The first fall frost typically arrives around 10/01, about 140 frost-free days later.
The USDA Plant Hardiness Zone Map puts Prompton in Zone 6a (-10 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 5 weeks of growing season left in Prompton before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/14 isn't a guarantee
05/14 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 05/29 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Prompton compares
Prompton's growing season runs about 140 days, ranking 37,164 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 2,032 of 2,088.
Learn more
local microclimates covers what one yard in Prompton can differ from the 18456 normal. zone vs. frost date covers why Zone 6a and Prompton's frost date answer different questions.