Castle Shannon, PA 15234 Frost Dates
When can you plant in Castle Shannon, PA?
Around 04/18 is the usual last spring frost, about 233 days away. The first fall frost typically arrives around 10/28, about 193 frost-free days later.
Castle Shannon sits in USDA Zone 6b (-5 to 0°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
About 9 weeks of growing season left in Castle Shannon before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 04/02 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 Castle Shannon compares
At roughly 193 frost-free days, Castle Shannon places 19,825 of 40,283 ZIP codes in this dataset. Within PA, it ranks 421 of 2,088.
Learn more
zone vs. frost date covers why Zone 6b and Castle Shannon's frost date answer different questions. the frost range covers how to read the range around Castle Shannon's dates instead of trusting one.