Frost Dates for 02155 — Medford, Massachusetts

Half of springs at Boston Logan International Airport, MA see their last 32°F night by April 4; only one in ten is past it by March 25, and one in ten still has one after April 17. Planting tender crops after April 8 leaves a 30% risk of a frost on them, after April 11 20%, and after April 17 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 51% of the 71 Massachusetts stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 9 in half of years, as early as October 29 one year in ten, and holds off past November 22 one year in ten. A hard freeze of 28°F follows 12 days later, around November 21; in spring the one-in-ten date for 28°F is April 6, 11 days before the 32°F one. The freeze-free season lasts 218 days in a typical year, the longest of the 71 Massachusetts stations; it reaches 235 days one year in ten and falls short of 201 one year in ten. On average 92 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 April 17, and return around October 29. Severe cold of 16°F or below comes every winter, usually between December 23 and March 2.

July is the warmest month at Boston Logan International Airport, MA, averaging 82°F by day and 66°F at night; January is the coldest at 37°F and 23°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 74% of years.

Warmth for growing adds up to 3,050 growing degree days a year (base 50°F), more than at 92% of the 71 Massachusetts stations. 30% of them (903) have built up by the end of June, and July adds the most, 745. Precipitation totals 43.7 inches a year, most in December (4.3") and least in February (3.2"); May to September bring 40% of it.

The nearest other station, Reading, MA, 7 miles north of Medford, has a last frost 21 days later (April 25), a first frost 23 days earlier (October 17), a season 44 days shorter.

The first measurable snow (0.1 inch or more) in Medford usually arrives around December 2, and the last of the season around March 29. Those are the middle dates across the winters of 1991–2020 at Boston Logan International Airport, MA, 6.5 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 6 days after the last snow.

ZIP 02155 is 7 miles from Boston Logan International Airport, MA, which stands at 12 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 24 other ZIP codes share the station; its figures are presented in full for 02148 (Malden). The 2023 USDA Plant Hardiness Zone Map lists ZIP 02155 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.