Frost Dates for 03031 — Amherst, New Hampshire

Half of springs at E Milford, NH see their last 32°F night by April 28; only one in ten is past it by April 18, and one in ten still has one after May 12. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 12 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 25% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 8 in half of years, as early as September 28 one year in ten, and holds off past October 22 one year in ten. A hard freeze of 28°F follows 11 days later, around October 19; in spring the one-in-ten date for 28°F is April 28, 14 days before the 32°F one. The freeze-free season lasts 161 days in a typical year, longer than at 76% of the 51 New Hampshire stations; it reaches 177 days one year in ten and falls short of 144 one year in ten. On average 154 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 10, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 24 and March 19.

July is the warmest month at E Milford, NH, averaging 83°F by day and 60°F at night; January is the coldest at 34°F and 14°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 41% of years.

Warmth for growing adds up to 2,525 growing degree days a year (base 50°F), more than at 86% of the 51 New Hampshire stations. 31% of them (790) have built up by the end of June, and July adds the most, 665. Precipitation totals 47.1 inches a year, most in October (4.8") and least in February (3.3"); May to September bring 41% of it.

The nearest other station, Milford, NH, 2 miles southwest of Amherst, has a last frost 5 days later (May 3), a first frost 3 days earlier (October 5), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Amherst usually arrives around November 25, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Milford, NH, 2.3 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 33 days after the last snow.

ZIP 03031 is 2 miles from E Milford, NH, which stands at 240 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 03031 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.