Frost Dates for 05446 — Colchester, Vermont

Half of springs at Essex Junction 1 N, VT see their last 32°F night by May 2; only one in ten is past it by April 21, and one in ten still has one after May 17. Planting tender crops after May 8 leaves a 30% risk of a frost on them, after May 12 20%, and after May 17 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 24% of the 41 Vermont stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 11 in half of years, as early as September 30 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 13 days later, around October 24; in spring the one-in-ten date for 28°F is May 5, 12 days before the 32°F one. The freeze-free season lasts 160 days in a typical year, longer than at 80% of the 41 Vermont stations; it reaches 178 days one year in ten and falls short of 141 one year in ten. On average 158 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 14 days longer, to about May 16, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 25 and March 29.

July is the warmest month at Essex Junction 1 N, VT, averaging 81°F by day and 61°F at night; January is the coldest at 28°F and 10°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 57% of years.

Warmth for growing adds up to 2,552 growing degree days a year (base 50°F), more than at 90% of the 41 Vermont stations. 32% of them (816) have built up by the end of June, and July adds the most, 652. Precipitation totals 42.3 inches a year, most in June (4.6") and least in February (2.1"); May to September bring 50% of it.

The nearest other station, Burlington International Airport, VT, 6 miles southeast of Colchester, has a last frost 3 days earlier (April 29), a first frost 4 days later (October 15), a season 9 days longer.

The first measurable snow (0.1 inch or more) in Colchester usually arrives around November 9, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at Essex Junction 1 N, VT, 4.6 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 21 days after the last snow.

ZIP 05446 is 5 miles from Essex Junction 1 N, VT, which stands at 340 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 05452 (Essex Junction). The 2023 USDA Plant Hardiness Zone Map lists ZIP 05446 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.