Thurmont, MD 21788 Frost Dates
Frost dates for Thurmont, MD, ZIP 21788
The last spring frost here typically falls around 04/14, about 229 days from today. The first fall frost typically arrives around 10/30, about 197 frost-free days later.
The USDA Plant Hardiness Zone Map puts Thurmont 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 Thurmont has about 9 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.
How much risk comes with planting early here
04/14 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. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Thurmont compares
At roughly 197 frost-free days, Thurmont places 18,661 of 40,283 ZIP codes in this dataset. Within MD, it ranks 478 of 583.
Learn more
local microclimates explains what one yard in Thurmont can differ from the 21788 normal, and zone vs. frost date explains why Zone 7a and Thurmont's frost date answer different questions.