FrostDateCheck

Marlborough, MA 01752 Frost Dates

01752, near Marlborough, MA: the frost window

Zone 6b

Around 05/02 is the usual last spring frost, about 247 days away. Fall's first freeze usually shows up around 10/06, roughly 156 days after the last spring frost.

Marlborough sits in USDA Zone 6b (-5 to 0°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.

Stretching the season past the first frost

Marlborough's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.

Why 05/02 isn't a guarantee

05/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/22 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.

Marlborough against the rest of the dataset

Marlborough's growing season runs about 156 days, ranking 33,519 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 619 of 712.

Learn more

Two guides worth reading on 01752: zone vs. frost date, on why Zone 6b and Marlborough's frost date answer different questions, and the frost range, on how to read the range around Marlborough's dates instead of trusting one.