Hillsboro, MD 21641 Frost Dates
21641, near Hillsboro, MD: the frost window
Typically, the last spring freeze lands around 04/01, roughly 216 days out. Fall's first freeze usually shows up around 11/07, roughly 220 days after the last spring frost.
Hillsboro 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
Hillsboro'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
04/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/18 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.
Hillsboro against the rest of the dataset
At roughly 220 frost-free days, Hillsboro places 12,908 of 40,283 ZIP codes in this dataset. Within MD, it ranks 195 of 583.
Learn more
Two guides worth reading on 21641: local microclimates, on what one yard in Hillsboro can differ from the 21641 normal, and zone vs. frost date, on why Zone 7b and Hillsboro's frost date answer different questions.