Marlborough, MA 01503 Frost Dates
01503, near Marlborough, MA: the frost window
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.
How much risk comes with planting early here
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 33,511 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 611 of 712.
Learn more
Two guides worth reading on 01503: local microclimates, on what one yard in Marlborough can differ from the 01503 normal, and zone vs. frost date, on why Zone 6b and Marlborough's frost date answer different questions.