Gaithersburg, MD 20891 Frost Dates
Frost dates for Gaithersburg, MD, ZIP 20891
Typically, the last spring freeze lands around 04/01, roughly 216 days out. The first fall frost typically arrives around 11/06, about 219 frost-free days later.
The USDA Plant Hardiness Zone Map puts Gaithersburg 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
Zone 7b around Gaithersburg has about 10 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.
The actual range around Gaithersburg's last frost
04/01 is the middle of 30 years of NOAA records, not a promise. Plant by 03/19 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 Gaithersburg compares
About 219 days separate Gaithersburg's last and first frost, putting it 12,939 of 40,283 ZIP codes nationally. Within MD, it ranks 212 of 583.
Learn more
the frost range explains how to read the range around Gaithersburg's dates instead of trusting one, and local microclimates explains what one yard in Gaithersburg can differ from the 20891 normal.