Frost Dates for 03257 — New London, New Hampshire

Half of springs at Mt Sunapee, NH see their last 32°F night by May 2; only one in ten is past it by April 21, and one in ten still has one after May 17. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 17 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 76% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 9 in half of years, as early as September 27 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 12 days later, around October 21; in spring the one-in-ten date for 28°F is May 3, 14 days before the 32°F one. The freeze-free season lasts 158 days in a typical year, longer than at 71% of the 51 New Hampshire stations; it reaches 176 days one year in ten and falls short of 140 one year in ten. On average 152 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about May 14, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 26 and March 25.

July is the warmest month at Mt Sunapee, NH, averaging 79°F by day and 59°F at night; January is the coldest at 29°F and 13°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 58% of years.

Warmth for growing adds up to 2,177 growing degree days a year (base 50°F), fewer than at 61% of the 51 New Hampshire stations. 30% of them (662) have built up by the end of June, and July adds the most, 590. Precipitation totals 48.4 inches a year, most in October (5.5") and least in February (3.1"); May to September bring 43% of it.

The nearest other station, Newport, NH, 10 miles west of New London and 505 feet lower, has a last frost 12 days later (May 14), a first frost 8 days earlier (October 1), a season 18 days shorter.

The first measurable snow (0.1 inch or more) in New London usually arrives around November 25, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Mt Sunapee, NH, 7.2 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 27 days after the last snow.

ZIP 03257 is 7 miles from Mt Sunapee, NH, which stands at 1,275 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03257 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.