Frost Dates for 04040 — Harrison, Maine

Half of springs at Bridgton 3 NW, ME see their last 32°F night by May 5; only one in ten is past it by April 26, and one in ten still has one after May 17. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 13 20%, and after May 17 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 52 Maine stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 22 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 14 days later, around October 19; in spring the one-in-ten date for 28°F is May 4, 13 days before the 32°F one. The freeze-free season lasts 151 days in a typical year, shorter than at 48% of the 52 Maine stations; it reaches 169 days one year in ten and falls short of 134 one year in ten. On average 177 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 18, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 25 and March 26.

July is the warmest month at Bridgton 3 NW, ME, averaging 78°F by day and 58°F at night; January is the coldest at 28°F and 7°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 76% of years.

Warmth for growing adds up to 1,946 growing degree days a year (base 50°F), fewer than at 58% of the 52 Maine stations. 29% of them (573) have built up by the end of June, and July adds the most, 549. Precipitation totals 50.7 inches a year, most in October (5.6") and least in January (3.5"); May to September bring 41% of it.

The nearest other station, Bethel 6 SSE, ME, 16 miles north of Harrison and 282 feet higher, has a last frost 1 day later (May 6), a first frost 3 days earlier (October 2), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Harrison 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 Bridgton 3 NW, ME, 5.2 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 29 days after the last snow.

ZIP 04040 is 5 miles from Bridgton 3 NW, ME, which stands at 508 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 04009 (Bridgton). The 2023 USDA Plant Hardiness Zone Map lists ZIP 04040 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.