Frost Dates for 04055 — Naples, Maine

Half of springs at East Hiram, ME see their last 32°F night by May 12; only one in ten is past it by May 1, and one in ten still has one after May 25. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 20 20%, and after May 25 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 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 10 days later, around October 11; in spring the one-in-ten date for 28°F is May 10, 15 days before the 32°F one. The freeze-free season lasts 140 days in a typical year, shorter than at 75% of the 52 Maine stations; it reaches 158 days one year in ten and falls short of 123 one year in ten. On average 185 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 25, and return around September 21. Severe cold of 16°F or below comes every winter, usually between November 20 and March 30.

July is the warmest month at East Hiram, ME, averaging 79°F by day and 56°F at night; January is the coldest at 29°F and 6°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 90% of years.

Warmth for growing adds up to 1,897 growing degree days a year (base 50°F), fewer than at 69% of the 52 Maine stations. 29% of them (554) have built up by the end of June, and July adds the most, 539. Precipitation totals 49.8 inches a year, most in October (5.4") and least in January (3.3"); May to September bring 41% of it.

The nearest other station, Windham 2NW, ME, 10 miles southeast of Naples, has a last frost 12 days earlier (April 30), a first frost 19 days later (October 20), a season 32 days longer.

The first measurable snow (0.1 inch or more) in Naples usually arrives around November 18, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at East Hiram, ME, 9.4 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 36 days after the last snow.

ZIP 04055 is 9 miles from East Hiram, ME, which stands at 528 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 04055 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.