Rock Hall, MD 21661 Frost Dates
Frost dates for Rock Hall, MD, ZIP 21661
Typically, the last spring freeze lands around 04/03, roughly 218 days out. The first fall frost typically arrives around 11/05, about 217 frost-free days later.
The USDA Plant Hardiness Zone Map puts Rock Hall in Zone 8a (10 to 15°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 8a around Rock Hall has about 10 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 Rock Hall's last frost
04/03 is the middle of 30 years of NOAA records, not a promise. Plant by 03/20 and you're betting against frost in roughly 9 years out of 10. 04/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rock Hall compares
About 217 days separate Rock Hall's last and first frost, putting it 13,552 of 40,283 ZIP codes nationally. Within MD, it ranks 314 of 583.
Learn more
zone vs. frost date explains why Zone 8a and Rock Hall's frost date answer different questions, and the frost range explains how to read the range around Rock Hall's dates instead of trusting one.