Frost Dates for 04443 — Guilford, Maine

Half of springs at Sebec Lake, ME see their last 32°F night by May 16; only one in ten is past it by May 3, and one in ten still has one after June 1. Planting tender crops after May 22 leaves a 30% risk of a frost on them, after May 27 20%, and after June 1 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 94% of the 52 Maine stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 19 one year in ten, and holds off past October 12 one year in ten. A hard freeze of 28°F follows 9 days later, around October 10; in spring the one-in-ten date for 28°F is May 16, 16 days before the 32°F one. The freeze-free season lasts 135 days in a typical year, shorter than at 87% of the 52 Maine stations; it reaches 153 days one year in ten and falls short of 115 one year in ten. On average 196 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 May 29, and return around September 20. Severe cold of 16°F or below comes every winter, usually between November 18 and April 4.

July is the warmest month at Sebec Lake, ME, averaging 78°F by day and 55°F at night; January is the coldest at 24°F and 3°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 12% of years.

Warmth for growing adds up to 1,730 growing degree days a year (base 50°F), fewer than at 88% of the 52 Maine stations. 28% of them (478) have built up by the end of June, and July adds the most, 515. Precipitation totals 48.5 inches a year, most in October (5.2") and least in February (3.2"); May to September bring 41% of it.

The nearest other station, Dover-Foxcroft Wwtp, ME, 10 miles southeast of Guilford, has a last frost 1 day earlier (May 15), a first frost 3 days earlier (September 28), a season 1 day shorter.

The first measurable snow (0.1 inch or more) in Guilford usually arrives around November 4, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Sebec Lake, ME, 7 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 33 days after the last snow.

ZIP 04443 is 7 miles from Sebec Lake, ME, which stands at 380 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 04443 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.