Frederick, MD 21701 Frost Dates
21701, near Frederick, MD: the frost window
Typically, the last spring freeze lands around 04/02, roughly 217 days out. Fall's first freeze usually shows up around 11/06, roughly 218 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Frederick in Zone 7a (0 to 5°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
Frederick'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.
How much risk comes with planting early here
04/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/17 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.
Frederick against the rest of the dataset
Frederick's growing season runs about 218 days, ranking 13,172 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 241 of 583.
Learn more
Two guides worth reading on 21701: the frost range, on how to read the range around Frederick's dates instead of trusting one, and local microclimates, on what one yard in Frederick can differ from the 21701 normal.