Frost Dates for 02770 — Rochester, Massachusetts

Half of springs at Rochester, MA see their last 32°F night by April 23; only one in ten is past it by April 10, and one in ten still has one after May 7. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 3 20%, and after May 7 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 21 in half of years, as early as October 6 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 13 days later, around November 3; in spring the one-in-ten date for 28°F is April 23, 14 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, longer than at 73% of the 71 Massachusetts stations; it reaches 198 days one year in ten and falls short of 160 one year in ten. On average 115 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 5, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 13 and March 7.

July is the warmest month at Rochester, MA, averaging 82°F by day and 63°F at night; January is the coldest at 38°F and 20°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 26% of years.

Warmth for growing adds up to 2,755 growing degree days a year (base 50°F), more than at 63% of the 71 Massachusetts stations. 29% of them (794) have built up by the end of June, and July adds the most, 696. Precipitation totals 53.6 inches a year, most in March (5.7") and least in July (3.4"); May to September bring 37% of it.

The nearest other station, New Bedford Municipal Airport, MA, 8 miles southwest of Rochester, has a last frost 6 days later (April 29), a first frost 6 days earlier (October 15), a season 13 days shorter.

The first measurable snow (0.1 inch or more) in Rochester usually arrives around December 22, and the last of the season around March 17. Those are the middle dates across the winters of 1991–2020 at Rochester, MA, 4.4 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 02770 is 4 miles from Rochester, MA, which stands at 65 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 02347 (Lakeville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 02770 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.