Preston, MD 21609 Frost Dates
When can you plant in Preston, MD?
Around 04/01 is the usual last spring frost, about 216 days away. The first fall frost typically arrives around 11/07, about 220 frost-free days later.
The USDA Plant Hardiness Zone Map puts Preston in Zone 7b (5 to 10°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 10 weeks of growing season left in Preston before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/01 isn't a guarantee
04/01 is the middle of 30 years of NOAA records, not a promise. Plant by 03/18 and you're betting against frost in roughly 9 years out of 10. 04/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Preston compares
About 220 days separate Preston's last and first frost, putting it 12,870 of 40,283 ZIP codes nationally. Within MD, it ranks 190 of 583.
Learn more
local microclimates covers what one yard in Preston can differ from the 21609 normal. zone vs. frost date covers why Zone 7b and Preston's frost date answer different questions.