Union Bridge, MD 21791 Frost Dates
Frost dates for Union Bridge, MD, ZIP 21791
The last spring frost here typically falls around 04/22, about 237 days from today. The first fall frost typically arrives around 10/20, about 179 frost-free days later.
Union Bridge sits in USDA Zone 7a (0 to 5°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 7a around Union Bridge has about 8 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 Union Bridge's last frost
04/22 is the middle of 30 years of NOAA records, not a promise. Plant by 04/07 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Union Bridge compares
About 179 days separate Union Bridge's last and first frost, putting it 25,404 of 40,283 ZIP codes nationally. Within MD, it ranks 555 of 583.
Learn more
zone vs. frost date explains why Zone 7a and Union Bridge's frost date answer different questions, and the frost range explains how to read the range around Union Bridge's dates instead of trusting one.