Baltimore, MD 21233 Frost Dates
21233, near Baltimore, MD: the frost window
The last spring frost here typically falls around 03/24, about 208 days from today. Fall's first freeze usually shows up around 11/21, roughly 244 days after the last spring frost.
Zone 8a (10 to 15°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 Baltimore, not a forecast for this year.
Stretching the season past the first frost
Baltimore's growing season runs out in roughly 12 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/24 isn't a guarantee
03/24 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/08 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/04 and only about 1 year in 10 sees frost after that.
Baltimore against the rest of the dataset
At roughly 244 frost-free days, Baltimore places 8,168 of 40,283 ZIP codes in this dataset. Within MD, it ranks 37 of 583.
Learn more
Two guides worth reading on 21233: local microclimates, on what one yard in Baltimore can differ from the 21233 normal, and zone vs. frost date, on why Zone 8a and Baltimore's frost date answer different questions.