Baltimore, MD 21278 Frost Dates
Frost dates for Baltimore, MD, ZIP 21278
Typically, the last spring freeze lands around 03/24, roughly 208 days out. The first fall frost typically arrives around 11/21, about 244 frost-free days later.
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.
What to do before the first frost
Zone 8a 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.
The actual range around Baltimore's last frost
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 8,178 of 40,283 ZIP codes in this dataset. Within MD, it ranks 47 of 583.
Learn more
local microclimates explains what one yard in Baltimore can differ from the 21278 normal, and zone vs. frost date explains why Zone 8a and Baltimore's frost date answer different questions.