Marlborough, MA 01805 Frost Dates
Frost dates for Marlborough, MA, ZIP 01805
Around 05/02 is the usual last spring frost, about 247 days away. The first fall frost typically arrives around 10/06, about 156 frost-free days later.
The USDA Plant Hardiness Zone Map puts Marlborough in Zone 6b (-5 to 0°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 6b around Marlborough has about 6 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 Marlborough's last frost
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/22 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Marlborough compares
Marlborough's growing season runs about 156 days, ranking 33,523 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 623 of 712.
Learn more
local microclimates explains what one yard in Marlborough can differ from the 01805 normal, and zone vs. frost date explains why Zone 6b and Marlborough's frost date answer different questions.