Boston, MA 02203 Frost Dates
Frost dates for Boston, MA, ZIP 02203
The last spring frost here typically falls around 04/04, about 219 days from today. The first fall frost typically arrives around 11/09, about 218 frost-free days later.
Zone 7a (0 to 5°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 Boston, not a forecast for this year.
What to do before the first frost
Zone 7a around Boston 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.
Why 04/04 isn't a guarantee
04/04 is the middle of 30 years of NOAA records, not a promise. Plant by 03/25 and you're betting against frost in roughly 9 years out of 10. 04/17 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Boston compares
Boston's growing season runs about 218 days, ranking 13,140 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 7 of 712.
Learn more
the frost range explains how to read the range around Boston's dates instead of trusting one, and local microclimates explains what one yard in Boston can differ from the 02203 normal.