Marlborough, MA 01705 Frost Dates
01705, near Marlborough, MA: the frost window
Typically, the last spring freeze lands around 05/02, roughly 247 days out. Fall's first freeze usually shows up around 10/06, roughly 156 days after the last spring frost.
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.
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 33,514 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 614 of 712.
Learn more
Two guides worth reading on 01705: local microclimates, on what one yard in Marlborough can differ from the 01705 normal, and zone vs. frost date, on why Zone 6b and Marlborough's frost date answer different questions.