Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 05640 — Adamant, VT

ZIP code 05640 (Adamant, Washington County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 4 and the first fall frost October 5.

Where ZIP 05640 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostMay 4

First frostOct 5

2012 zone4b

Was 4b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Adamant, VT…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Adamant, VT

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 4median — 50% chance of a later frost

Safe for tender plantsMay 18only 10% chance of frost after

First fall frostOctober 5median — 10% chance by Sep 21

Growing season153 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 19.

From the NOAA station Worcester 2 W, VT — 5 miles away, elevation 1,362 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 05640

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 23 – Apr 6

SpinachSow outdoors · Mar 23 – Apr 13

Broccoli, cabbageStart indoors · Feb 23 – Mar 9

Broccoli, cabbageTransplant · Apr 13 – Apr 27

Onion setsPlant outdoors · Apr 6 – Apr 20

PotatoesPlant outdoors · Apr 13 – Apr 27

LettuceSow outdoors · Apr 6 – Apr 20

Carrots, beetsSow outdoors · Apr 13 – Apr 27

TomatoesStart indoors · Mar 9 – Mar 23

TomatoesTransplant · May 11 – May 25

Peppers, eggplantStart indoors · Feb 23 – Mar 9

Peppers, eggplantTransplant · May 18 – Jun 1

BeansSow outdoors · May 11 – May 25

Sweet cornSow outdoors · May 11 – May 25

Cucumbers, squashSow outdoors · May 11 – May 25

Fall lettuce, spinachSow outdoors · Aug 10 – Aug 24

GarlicPlant cloves · Sep 21 – Oct 26

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 4) and first fall frost (Oct 5) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 05640 came on Apr 17 — 8 days earlier than the 1991–2020 average (Apr 25).

average
Apr 252026
Apr 17

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 5a in Vermont

459 plants native to the lower 48 states, recorded in Vermont, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Adamant, VT.

Soil in Adamant, VT

The soil mapped at the center of ZIP 05640 is Tunbridge — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer

pH3.5strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter85%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Tunbridge-Lyman complex, 15 to 35 percent slopes, very rocky.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 05640; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Adamant, VT

Summer high77 °Faverage high, July

Winter low8 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights165nights a year at 32 °F or less

Growing degree days1,932base 50 °F — the season’s usable heat

Longest day15 h 32 mindaylight on June 21

Shortest day8 h 51 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation46.3 inper year, rain and melted snow

Snowfall126 inper year; 130 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Worcester 2 W, VT (5 mi away); precipitation: Worcester 2 W, VT (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

5 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

056664b

North Montpelier, VT · 3 mi

056485a

Calais, VT · 3 mi

056514b

East Montpelier, VT · 4 mi

056825a

Worcester, VT · 5 mi

056504b

East Calais, VT · 5 mi

056675a

Plainfield, VT · 6 mi

056034b

Montpelier, VT · 7 mi

056044b

Montpelier, VT · 7 mi

Vermont planting zones →

Questions about 05640

What planting zone is ZIP code 05640?

ZIP code 05640 (Adamant, VT) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Adamant, VT?

The median last spring frost (32 °F) near 05640 is May 4; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Worcester 2 W station.

When is the first frost in Adamant, VT?

The median first fall frost near 05640 is October 5, giving a median frost-free growing season of 153 days.

When should I plant tomatoes in 05640?

Start tomato seeds indoors around Mar 9 – Mar 23 and set transplants outside around May 11 – May 25, one to three weeks after the median last frost.

How much rain and snow does 05640 get?

About 46.3 inches of precipitation a year and 126 inches of snowfall (NOAA 1991–2020 normals, Worcester 2 W station).

How hot do summers get in Adamant, VT?

The average high peaks at 77 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 05640 have?

The USDA soil survey maps Tunbridge at the center of ZIP 05640: moderately decomposed plant material, well drained, pH about 3.5 (strongly acidic).

Did spring come early in Adamant, VT in 2026?

Spring leaf-out near 05640 came on Apr 17 in 2026, 8 days earlier than the 1991–2020 average (Apr 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Adamant, VT?

Long-day onions: the longest day near 05640 is 15 h 32 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 05640 change?

Yes. The 2012 USDA map put 05640 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.