Frost Dates for 01430 — Ashburnham, Massachusetts

Half of springs at Ashburnham N, MA see their last 32°F night by May 5; only one in ten is past it by April 25, and one in ten still has one after May 19. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 15 20%, and after May 19 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 51% of the 71 Massachusetts stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 7 in half of years, as early as September 24 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 11 days later, around October 18; in spring the one-in-ten date for 28°F is May 7, 12 days before the 32°F one. The freeze-free season lasts 152 days in a typical year, shorter than at 92% of the 71 Massachusetts stations; it reaches 168 days one year in ten and falls short of 135 one year in ten. On average 163 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 18, and return around September 28. Severe cold of 16°F or below comes every winter, usually between November 27 and March 25.

July is the warmest month at Ashburnham N, MA, averaging 79°F by day and 58°F at night; January is the coldest at 31°F and 11°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 71% of years.

Warmth for growing adds up to 2,132 growing degree days a year (base 50°F), fewer than at 99% of the 71 Massachusetts stations. 30% of them (634) have built up by the end of June, and July adds the most, 580. Precipitation totals 48.8 inches a year, most in October (5.1") and least in January (3.2"); May to September bring 43% of it.

The nearest other station, Ashburnham, MA, 3 miles south of Ashburnham, has a last frost 3 days earlier (May 2), a first frost 6 days later (October 13), a season 11 days longer.

The first measurable snow (0.1 inch or more) in Ashburnham usually arrives around December 6, and the last of the season around March 29. Those are the middle dates across the winters of 1991–2020 at Ashburnham N, MA, 0.3 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 37 days after the last snow.

ZIP 01430 is under a mile from Ashburnham N, MA, which stands at 1,146 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 01430 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.