Baltimore, MD 21230 Frost Dates
Frost dates for Baltimore, MD, ZIP 21230
The last spring frost here typically falls around 03/24, about 208 days from today. The first fall frost typically arrives around 11/21, about 244 frost-free days later.
Baltimore sits in USDA Zone 8a (10 to 15°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 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.
How much risk comes with planting early here
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
About 244 days separate Baltimore's last and first frost, putting it 8,166 of 40,283 ZIP codes nationally. Within MD, it ranks 35 of 583.
Learn more
local microclimates explains what one yard in Baltimore can differ from the 21230 normal, and zone vs. frost date explains why Zone 8a and Baltimore's frost date answer different questions.