Frost Dates for 05001 — White River Junction, Vermont

Half of springs at Lebanon Municipal Airport, NH see their last 32°F night by May 9; only one in ten is past it by April 27, and one in ten still has one after May 24. Planting tender crops after May 16 leaves a 30% risk of a frost on them, after May 20 20%, and after May 24 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 6 in half of years, as early as September 23 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 9 days later, around October 15; in spring the one-in-ten date for 28°F is May 11, 13 days before the 32°F one. The freeze-free season lasts 148 days in a typical year, longer than at 61% of the 41 Vermont stations; it reaches 167 days one year in ten and falls short of 128 one year in ten. On average 163 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 22, and return around September 26. Severe cold of 16°F or below comes every winter, usually between November 21 and March 29.

July is the warmest month at Lebanon Municipal Airport, NH, averaging 83°F by day and 58°F at night; January is the coldest at 30°F and 9°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 80% of years.

Warmth for growing adds up to 2,364 growing degree days a year (base 50°F), more than at 80% of the 41 Vermont stations. 31% of them (736) have built up by the end of June, and July adds the most, 628. Precipitation totals 38.0 inches a year, most in July (4.0") and least in February (2.1"); May to September bring 48% of it.

The nearest other station, N Hartland Lake, VT, 4 miles south of White River Junction, has a last frost 1 day earlier (May 8), the same first-frost date, a season 2 days longer.

The first measurable snow (0.1 inch or more) in White River Junction usually arrives around November 19, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Hanover, NH, 5.1 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 37 days after the last snow.

ZIP 05001 is 4 miles from Lebanon Municipal Airport, NH, which stands at 598 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 03766 (Lebanon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 05001 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.