Rockville, MD 20850 Frost Dates
Rockville, MD: when does the frost end?
The last spring frost here typically falls around 04/01, about 216 days from today. Fall's first freeze usually shows up around 11/06, roughly 219 days after the last spring frost.
Rockville 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.
Stretching the season past the first frost
With roughly 10 weeks until Rockville'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.
Rockville against the rest of the dataset
About 219 days separate Rockville's last and first frost, putting it 12,952 of 40,283 ZIP codes nationally. Within MD, it ranks 225 of 583.
Learn more
Before leaning on 20850's figures: zone vs. frost date explains why Zone 7b and Rockville's frost date answer different questions, while the frost range explains how to read the range around Rockville's dates instead of trusting one.