Baltimore, MD 21270 Frost Dates
Frost dates for Baltimore, MD, ZIP 21270
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.
The USDA Plant Hardiness Zone Map puts Baltimore in Zone 7b (5 to 10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's 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.
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
About 244 days separate Baltimore's last and first frost, putting it 8,175 of 40,283 ZIP codes nationally. Within MD, it ranks 44 of 583.
Learn more
zone vs. frost date explains why Zone 7b and Baltimore's frost date answer different questions, and the frost range explains how to read the range around Baltimore's dates instead of trusting one.