Gaithersburg, MD 20825 Frost Dates
20825, near Gaithersburg, MD: the frost window
Around 04/01 is the usual last spring frost, about 216 days away. Fall's first freeze usually shows up around 11/06, roughly 219 days after the last spring frost.
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.
Stretching the season past the first frost
Gaithersburg's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Gaithersburg's last frost
04/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/15 and only about 1 year in 10 sees frost after that.
Gaithersburg against the rest of the dataset
Gaithersburg's growing season runs about 219 days, ranking 12,926 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 199 of 583.
Learn more
Two guides worth reading on 20825: local microclimates, on what one yard in Gaithersburg can differ from the 20825 normal, and zone vs. frost date, on why Zone 7b and Gaithersburg's frost date answer different questions.