Poolesville, MD 20837 Frost Dates
20837, near Poolesville, MD: the frost window
Typically, the last spring freeze lands around 04/13, roughly 228 days out. Fall's first freeze usually shows up around 10/26, roughly 195 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Poolesville 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
Poolesville's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/13 isn't a guarantee
04/13 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/01 and only about 1 year in 10 sees frost after that.
Poolesville against the rest of the dataset
About 195 days separate Poolesville's last and first frost, putting it 19,248 of 40,283 ZIP codes nationally. Within MD, it ranks 506 of 583.
Learn more
Two guides worth reading on 20837: zone vs. frost date, on why Zone 7b and Poolesville's frost date answer different questions, and the frost range, on how to read the range around Poolesville's dates instead of trusting one.