Bel Air, MD 21131 Frost Dates
21131, near Bel Air, MD: the frost window
The last spring frost here typically falls around 04/02, about 217 days from today. Fall's first freeze usually shows up around 11/07, roughly 220 days after the last spring frost.
Zone 7b (5 to 10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Bel Air, not a forecast for this year.
Stretching the season past the first frost
Bel Air'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.
Why 04/02 isn't a guarantee
04/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/13 and only about 1 year in 10 sees frost after that.
Bel Air against the rest of the dataset
Bel Air's growing season runs about 220 days, ranking 12,771 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 171 of 583.
Learn more
Two guides worth reading on 21131: the frost range, on how to read the range around Bel Air's dates instead of trusting one, and local microclimates, on what one yard in Bel Air can differ from the 21131 normal.