Frost Dates for 01373 — South Deerfield, Massachusetts

Half of springs at Leverett #2, MA 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 16. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 16 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 9 in half of years, as early as September 29 one year in ten, and holds off past October 25 one year in ten. A hard freeze of 28°F follows 14 days later, around October 23; in spring the one-in-ten date for 28°F is May 4, 12 days before the 32°F one. The freeze-free season lasts 160 days in a typical year, shorter than at 75% of the 71 Massachusetts stations; it reaches 179 days one year in ten and falls short of 142 one year in ten. On average 153 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 11 days longer, to about May 13, 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 Leverett #2, MA, averaging 83°F by day and 61°F at night; January is the coldest at 30°F and 12°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 55% of years.

Warmth for growing adds up to 2,606 growing degree days a year (base 50°F), fewer than at 56% of the 71 Massachusetts stations. 32% of them (828) have built up by the end of June, and July adds the most, 677.

The nearest other station, Greenfield #3, MA, 7 miles north of South Deerfield and 185 feet lower, has a last frost 1 day earlier (May 1), a first frost 2 days later (October 11), a season 2 days longer.

The first measurable snow (0.1 inch or more) in South Deerfield usually arrives around November 25, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Sunderland, MA, 4.1 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 01373 is 5 miles from Leverett #2, MA, which stands at 315 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 01373 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.