Gaithersburg, MD 20849 Frost Dates
Gaithersburg, MD: when does the frost end?
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
With roughly 10 weeks until Gaithersburg's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/01 isn't a guarantee
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
About 219 days separate Gaithersburg's last and first frost, putting it 12,930 of 40,283 ZIP codes nationally. Within MD, it ranks 203 of 583.
Learn more
Before leaning on 20849's figures: local microclimates explains what one yard in Gaithersburg can differ from the 20849 normal, while zone vs. frost date explains why Zone 7b and Gaithersburg's frost date answer different questions.