Baltimore, MD 21223 Frost Dates
Frost dates for Baltimore, MD, ZIP 21223
Around 03/24 is the usual last spring frost, about 208 days away. The first fall frost typically arrives around 11/21, about 244 frost-free days later.
Baltimore 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.
What to do before the first frost
Zone 7b around Baltimore has about 12 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 03/24 isn't a guarantee
03/24 is the middle of 30 years of NOAA records, not a promise. Plant by 03/08 and you're betting against frost in roughly 9 years out of 10. 04/04 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Baltimore compares
At roughly 244 frost-free days, Baltimore places 8,160 of 40,283 ZIP codes in this dataset. Within MD, it ranks 29 of 583.
Learn more
local microclimates explains what one yard in Baltimore can differ from the 21223 normal, and zone vs. frost date explains why Zone 7b and Baltimore's frost date answer different questions.