Frost Dates for 04043 — Kennebunk, Maine

Half of springs at Kennebunkport, ME see their last 32°F night by May 9; only one in ten is past it by April 28, and one in ten still has one after May 22. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 18 20%, and after May 22 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 33% of the 52 Maine stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 3 in half of years, as early as September 20 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 12 days later, around October 15; in spring the one-in-ten date for 28°F is May 12, 10 days before the 32°F one. The freeze-free season lasts 146 days in a typical year, shorter than at 67% of the 52 Maine stations; it reaches 165 days one year in ten and falls short of 128 one year in ten. On average 160 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 20, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 27 and March 22.

July is the warmest month at Kennebunkport, ME, averaging 77°F by day and 58°F at night; January is the coldest at 33°F and 13°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 82% of years.

Warmth for growing adds up to 1,878 growing degree days a year (base 50°F), fewer than at 71% of the 52 Maine stations. 26% of them (482) have built up by the end of June, and July adds the most, 538. Precipitation totals 52.0 inches a year, most in October (5.6") and least in January (3.7"); May to September bring 40% of it.

The nearest other station, Cape Neddick, ME, 12 miles southwest of Kennebunk, has a last frost 8 days earlier (May 1), a first frost 11 days later (October 14), a season 19 days longer.

The first measurable snow (0.1 inch or more) in Kennebunk usually arrives around December 4, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Kennebunkport, ME, 4.2 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 44 days after the last snow.

ZIP 04043 is 4 miles from Kennebunkport, ME, which stands at 20 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 04005 (Biddeford). The 2023 USDA Plant Hardiness Zone Map lists ZIP 04043 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.