Lebanon, NH 03748 Frost Dates
03748, near Lebanon, NH: the frost window
Typically, the last spring freeze lands around 05/21, roughly 266 days out. Fall's first freeze usually shows up around 09/26, roughly 127 days after the last spring frost.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Lebanon, not a forecast for this year.
Stretching the season past the first frost
Lebanon's growing season runs out in roughly 4 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/21 isn't a guarantee
05/21 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/05 and only about 1 year in 10 sees frost after that.
Lebanon against the rest of the dataset
At roughly 127 frost-free days, Lebanon places 38,611 of 40,283 ZIP codes in this dataset. Within NH, it ranks 247 of 260.
Learn more
Two guides worth reading on 03748: local microclimates, on what one yard in Lebanon can differ from the 03748 normal, and zone vs. frost date, on why Zone 5a and Lebanon's frost date answer different questions.