Manchester, NH 03101 Frost Dates
03101, near Manchester, NH: the frost window
Around 04/30 is the usual last spring frost, about 245 days away. Fall's first freeze usually shows up around 10/11, roughly 164 days after the last spring frost.
Zone 6a (-10 to -5°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 Manchester, not a forecast for this year.
Stretching the season past the first frost
Manchester'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 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Manchester against the rest of the dataset
About 164 days separate Manchester's last and first frost, putting it 30,817 of 40,283 ZIP codes nationally. Within NH, it ranks 30 of 260.
Learn more
Two guides worth reading on 03101: local microclimates, on what one yard in Manchester can differ from the 03101 normal, and zone vs. frost date, on why Zone 6a and Manchester's frost date answer different questions.