Gaithersburg, MD 20859 Frost Dates
Frost dates for Gaithersburg, MD, ZIP 20859
The last spring frost here typically falls around 04/01, about 216 days from today. The first fall frost typically arrives around 11/06, about 219 frost-free days later.
Gaithersburg sits in USDA Zone 7b (5 to 10°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
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
Gaithersburg's growing season runs about 219 days, ranking 12,932 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 205 of 583.
Learn more
zone vs. frost date explains why Zone 7b and Gaithersburg's frost date answer different questions, and the frost range explains how to read the range around Gaithersburg's dates instead of trusting one.