Frost Dates for 01570 — Webster, Massachusetts

Half of springs at Buffumville Lake, MA see their last 32°F night by May 1; only one in ten is past it by April 21, and one in ten still has one after May 13. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 8 20%, and after May 13 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 83% of the 71 Massachusetts stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 10 in half of years, as early as September 28 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 12 days later, around October 22; in spring the one-in-ten date for 28°F is May 1, 12 days before the 32°F one. The freeze-free season lasts 162 days in a typical year, shorter than at 66% of the 71 Massachusetts stations; it reaches 180 days one year in ten and falls short of 143 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 12, and return around October 2. Severe cold of 16°F or below comes every winter, usually between December 1 and March 16.

July is the warmest month at Buffumville Lake, MA, averaging 83°F by day and 60°F at night; January is the coldest at 34°F and 15°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 54% of years.

Warmth for growing adds up to 2,532 growing degree days a year (base 50°F), fewer than at 65% of the 71 Massachusetts stations. 30% of them (772) have built up by the end of June, and July adds the most, 663. Precipitation totals 48.9 inches a year, most in October (4.8") and least in February (3.2"); May to September bring 41% of it.

The nearest other station, W Thompson Lake, CT, 7 miles south of Webster and 160 feet lower, has the same 50% last-frost date, a first frost 1 day earlier (October 9), a season 1 day shorter.

The first measurable snow (0.1 inch or more) in Webster usually arrives around December 7, and the last of the season around March 23. Those are the middle dates across the winters of 1991–2020 at Buffumville Lake, MA, 5.3 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 39 days after the last snow.

ZIP 01570 is 5 miles from Buffumville Lake, MA, which stands at 520 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 01570 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.