Smithsburg, MD 21720 Frost Dates
21720, near Smithsburg, MD: the frost window
Typically, the last spring freeze lands around 04/25, roughly 240 days out. Fall's first freeze usually shows up around 10/19, roughly 176 days after the last spring frost.
Smithsburg sits in USDA Zone 7a (0 to 5°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
Smithsburg's growing season runs out in roughly 7 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 Smithsburg's last frost
04/25 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/11 and only about 1 year in 10 sees frost after that.
Smithsburg against the rest of the dataset
Smithsburg's growing season runs about 176 days, ranking 26,464 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 556 of 583.
Learn more
Two guides worth reading on 21720: the frost range, on how to read the range around Smithsburg's dates instead of trusting one, and local microclimates, on what one yard in Smithsburg can differ from the 21720 normal.