Concord, NH 03303 Frost Dates
03303, near Concord, NH: the frost window
Around 05/14 is the usual last spring frost, about 259 days away. Fall's first freeze usually shows up around 09/29, roughly 138 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Concord in Zone 5b (-15 to -10°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
Concord's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Concord's last frost
05/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/28 and only about 1 year in 10 sees frost after that.
Concord against the rest of the dataset
At roughly 138 frost-free days, Concord places 37,339 of 40,283 ZIP codes in this dataset. Within NH, it ranks 191 of 260.
Learn more
Two guides worth reading on 03303: local microclimates, on what one yard in Concord can differ from the 03303 normal, and zone vs. frost date, on why Zone 5b and Concord's frost date answer different questions.