Frost Dates for 03220 — Belmont, New Hampshire

Half of springs at Lakeport 2, NH see their last 32°F night by April 30; only one in ten is past it by April 19, and one in ten still has one after May 13. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 13 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 4 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 14 days later, around November 1; in spring the one-in-ten date for 28°F is April 30, 13 days before the 32°F one. The freeze-free season lasts 170 days in a typical year, longer than at 92% of the 51 New Hampshire stations; it reaches 188 days one year in ten and falls short of 153 one year in ten. On average 150 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 10 days longer, to about May 10, and return around October 5. Severe cold of 16°F or below comes every winter, usually between December 1 and March 22.

July is the warmest month at Lakeport 2, NH, averaging 82°F by day and 60°F at night; January is the coldest at 30°F and 12°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 46% of years.

Warmth for growing adds up to 2,482 growing degree days a year (base 50°F), more than at 76% of the 51 New Hampshire stations. 29% of them (732) have built up by the end of June, and July adds the most, 659. Precipitation totals 45.7 inches a year, most in October (4.8") and least in February (2.9"); May to September bring 44% of it.

The nearest other station, Franklin Falls Dam, NH, 9 miles west of Belmont, has a last frost 7 days later (May 7), a first frost 15 days earlier (October 3), a season 22 days shorter.

The first measurable snow (0.1 inch or more) in Belmont usually arrives around December 2, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Lakeport 2, NH, 6.2 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 30 days after the last snow.

ZIP 03220 is 6 miles from Lakeport 2, NH, which stands at 500 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 03246 (Laconia). The 2023 USDA Plant Hardiness Zone Map lists ZIP 03220 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.