Frost Dates for 04619 — Calais, Maine

Half of springs at Woodland, ME see their last 32°F night by April 21; only one in ten is past it by April 9, and one in ten still has one after May 2. Planting tender crops after April 26 leaves a 30% risk of a frost on them, after April 29 20%, and after May 2 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 26 in half of years, as early as October 7 one year in ten, and holds off past November 9 one year in ten. A hard freeze of 28°F follows 12 days later, around November 7; in spring the one-in-ten date for 28°F is April 22, 10 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, the longest of the 52 Maine stations; it reaches 206 days one year in ten and falls short of 165 one year in ten. On average 166 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 2, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 4 and March 18.

July is the warmest month at Woodland, ME, averaging 80°F by day and 62°F at night; January is the coldest at 28°F and 13°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 13% of years.

Warmth for growing adds up to 2,382 growing degree days a year (base 50°F), more than at 96% of the 52 Maine stations. 28% of them (659) have built up by the end of June, and July adds the most, 656. Precipitation totals 47.5 inches a year, most in October (5.3") and least in February (3.1"); May to September bring 38% of it.

The nearest other station, Wesley, ME, 25 miles southwest of Calais and 287 feet higher, has a last frost 11 days later (May 2), a first frost 11 days earlier (October 15), a season 21 days shorter.

The first measurable snow (0.1 inch or more) in Calais usually arrives around November 12, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Robbinston, ME, 8.1 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 5 days after the last snow.

ZIP 04619 is 8 miles from Woodland, ME, which stands at 123 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 04619 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.