Frost Dates for 03048 — Mason, New Hampshire

Half of springs at Greenville 1 NNE, NH see their last 32°F night by May 10; only one in ten is past it by April 26, and one in ten still has one after May 27. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 20 20%, and after May 27 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 98% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 6 in half of years, as early as September 25 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 12 days later, around October 18; in spring the one-in-ten date for 28°F is May 13, 14 days before the 32°F one. The freeze-free season lasts 147 days in a typical year, shorter than at 59% of the 51 New Hampshire stations; it reaches 168 days one year in ten and falls short of 128 one year in ten. On average 157 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 13 days longer, to about May 23, and return around September 28. Severe cold of 16°F or below comes every winter, usually between November 28 and March 22.

July is the warmest month at Greenville 1 NNE, NH, averaging 79°F by day and 58°F at night; January is the coldest at 30°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 75% of years.

Warmth for growing adds up to 2,103 growing degree days a year (base 50°F), fewer than at 69% of the 51 New Hampshire stations. 29% of them (619) have built up by the end of June, and July adds the most, 582. Precipitation totals 49.6 inches a year, most in October (5.4") and least in February (3.3"); May to September bring 40% of it.

The nearest other station, Milford, NH, 9 miles northeast of Mason and 580 feet lower, has a last frost 7 days earlier (May 3), a first frost 1 day earlier (October 5), a season 9 days longer.

The first measurable snow (0.1 inch or more) in Mason usually arrives around November 24, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Greenville 1 NNE, NH, 2.7 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 38 days after the last snow.

ZIP 03048 is 3 miles from Greenville 1 NNE, NH, which stands at 900 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 03071 (New Ipswich). The 2023 USDA Plant Hardiness Zone Map lists ZIP 03048 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.