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

Planting zone for 06831 — Greenwich, CT

ZIP code 06831 (Greenwich, Western Connecticut County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 12 and the first fall frost October 31.

Where ZIP 06831 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 12
First frostOct 31
2012 zone7a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Greenwich, CT…

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 Greenwich, CT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 12median — 50% chance of a later frost
Safe for tender plantsApril 27only 10% chance of frost after
First fall frostOctober 31median — 10% chance by Oct 15
Growing season200 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around November 13.

From the NOAA station Westchester Co. Airport, NY — 3 miles away, elevation 381 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 06831

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 1 – Mar 15
SpinachSow outdoors · Mar 1 – Mar 22
Broccoli, cabbageStart indoors · Feb 1 – Feb 15
Broccoli, cabbageTransplant · Mar 22 – Apr 5
Onion setsPlant outdoors · Mar 15 – Mar 29
PotatoesPlant outdoors · Mar 22 – Apr 5
LettuceSow outdoors · Mar 15 – Mar 29
Carrots, beetsSow outdoors · Mar 22 – Apr 5
TomatoesStart indoors · Feb 15 – Mar 1
TomatoesTransplant · Apr 19 – May 3
Peppers, eggplantStart indoors · Feb 1 – Feb 15
Peppers, eggplantTransplant · Apr 26 – May 10
BeansSow outdoors · Apr 19 – May 3
Sweet cornSow outdoors · Apr 19 – May 3
Cucumbers, squashSow outdoors · Apr 19 – May 3
Fall lettuce, spinachSow outdoors · Sep 5 – Sep 19
GarlicPlant cloves · Oct 17 – Nov 21
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 12) and first fall frost (Oct 31) 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 06831 came on Apr 1 — about the same time as the 1991–2020 average (Mar 31).

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 7a in Connecticut

546 plants native to the lower 48 states, recorded in Connecticut, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 65

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 106

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 191

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 157

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °F

Vines 10

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °F

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 Greenwich, CT.

Soil in Greenwich, CT

The soil mapped at the center of ZIP 06831 is Charlton — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
DrainageWell drainednatural drainage class
Organic matter95%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Charlton-Chatfield complex, 0 to 15 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 06831; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Greenwich, CT

Summer high83 °Faverage high, July
Winter low22 °Faverage low, January
Hot days10days a year at 90 °F or more
Freezing nights105nights a year at 32 °F or less
Growing degree days3,082base 50 °F — the season’s usable heat
Longest day15 h 08 mindaylight on June 21
Shortest day9 h 13 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation50.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 37 °F, low 22 °F 37°22° JanFebruary: average high 40 °F, low 24 °F 40°24° FebMarch: average high 48 °F, low 31 °F 48°31° MarApril: average high 59 °F, low 40 °F 59°40° AprMay: average high 69 °F, low 50 °F 69°50° MayJune: average high 78 °F, low 59 °F 78°59° JunJuly: average high 83 °F, low 65 °F 83°65° JulAugust: average high 81 °F, low 64 °F 81°64° AugSeptember: average high 74 °F, low 57 °F 74°57° SepOctober: average high 63 °F, low 46 °F 63°46° OctNovember: average high 52 °F, low 36 °F 52°36° NovDecember: average high 42 °F, low 28 °F 42°28° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.57 in precipitation 3.6 JanFebruary: 3.22 in precipitation 3.2 FebMarch: 4.36 in precipitation 4.4 MarApril: 4.06 in precipitation 4.1 AprMay: 4.56 in precipitation 4.6 MayJune: 4.55 in precipitation 4.5 JunJuly: 4.11 in precipitation 4.1 JulAugust: 4.64 in precipitation 4.6 AugSeptember: 5.04 in precipitation 5.0 SepOctober: 4.53 in precipitation 4.5 OctNovember: 3.68 in precipitation 3.7 NovDecember: 4.24 in precipitation 4.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Westchester Co. Airport, NY (3 mi away); precipitation: Putnam Lake, CT (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

105047a
Armonk, NY · 4 mi
068307a
Greenwich, CT · 4 mi
068077a
Cos Cob, CT · 4 mi
106107a
White Plains, NY · 4 mi
105777a
Purchase, NY · 4 mi
068367a
Greenwich, CT · 5 mi
106047a
West Harrison, NY · 5 mi
105737b
Port Chester, NY · 5 mi

All 3 ZIP codes in Greenwich → · Connecticut planting zones →

Questions about 06831

What planting zone is ZIP code 06831?

ZIP code 06831 (Greenwich, CT) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Greenwich, CT?

The median last spring frost (32 °F) near 06831 is April 12; after April 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Westchester Co. Airport station.

When is the first frost in Greenwich, CT?

The median first fall frost near 06831 is October 31, giving a median frost-free growing season of 200 days.

When should I plant tomatoes in 06831?

Start tomato seeds indoors around Feb 15 – Mar 1 and set transplants outside around Apr 19 – May 3, one to three weeks after the median last frost.

How much rain and snow does 06831 get?

About 50.6 inches of precipitation a year (NOAA 1991–2020 normals, Putnam Lake station).

How hot do summers get in Greenwich, CT?

The average high peaks at 83 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 06831 have?

The USDA soil survey maps Charlton at the center of ZIP 06831: moderately decomposed plant material, well drained.

Did spring come early in Greenwich, CT in 2026?

Spring leaf-out near 06831 came on Apr 1 in 2026, about the same as the 1991–2020 average (Mar 31), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Greenwich, CT?

Long-day onions: the longest day near 06831 is 15 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).