Frost Dates for 04609 — Bar Harbor, Maine

Half of springs at Acadia Np, ME see their last 32°F night by April 27; only one in ten is past it by April 15, and one in ten still has one after May 8. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 4 20%, and after May 8 10%. The 11 days between the even-odds date and the one-in-ten date is narrower than at 87% of the 52 Maine stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as October 6 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 11 days later, around November 2; in spring the one-in-ten date for 28°F is April 27, 11 days before the 32°F one. The freeze-free season lasts 177 days in a typical year, longer than at 94% of the 52 Maine stations; it reaches 196 days one year in ten and falls short of 157 one year in ten. On average 141 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 8, and return around October 8. Severe cold of 16°F or below comes every winter, usually between December 1 and March 19.

July is the warmest month at Acadia Np, ME, averaging 79°F by day and 60°F at night; January is the coldest at 33°F and 15°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 33% of years.

Warmth for growing adds up to 2,291 growing degree days a year (base 50°F), more than at 88% of the 52 Maine stations. 27% of them (620) have built up by the end of June, and July adds the most, 612. Precipitation totals 55.7 inches a year, most in October (5.9") and least in July (3.3"); May to September bring 36% of it.

The nearest other station, E Surry, ME, 12 miles northwest of Bar Harbor and 365 feet lower, has a last frost 11 days later (May 8), a first frost 13 days earlier (October 9), a season 25 days shorter.

The first measurable snow (0.1 inch or more) in Bar Harbor usually arrives around November 28, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Acadia Np, ME, 2 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 25 days after the last snow.

ZIP 04609 is 2 miles from Acadia Np, ME, which stands at 470 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 04609 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.