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

Planting zone for 06511 — New Haven, CT

ZIP code 06511 (New Haven, South Central Regional County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 17 and the first fall frost October 27.

Where ZIP 06511 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 17
First frostOct 27
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 New Haven, 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 New Haven, CT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 17median — 50% chance of a later frost
Safe for tender plantsMay 1only 10% chance of frost after
First fall frostOctober 27median — 10% chance by Oct 11
Growing season193 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 6.

From the NOAA station New Haven Tweed Airport, CT — 4 miles away, elevation 3 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 06511

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 6 – Mar 20
SpinachSow outdoors · Mar 6 – Mar 27
Broccoli, cabbageStart indoors · Feb 6 – Feb 20
Broccoli, cabbageTransplant · Mar 27 – Apr 10
Onion setsPlant outdoors · Mar 20 – Apr 3
PotatoesPlant outdoors · Mar 27 – Apr 10
LettuceSow outdoors · Mar 20 – Apr 3
Carrots, beetsSow outdoors · Mar 27 – Apr 10
TomatoesStart indoors · Feb 20 – Mar 6
TomatoesTransplant · Apr 24 – May 8
Peppers, eggplantStart indoors · Feb 6 – Feb 20
Peppers, eggplantTransplant · May 1 – May 15
BeansSow outdoors · Apr 24 – May 8
Sweet cornSow outdoors · Apr 24 – May 8
Cucumbers, squashSow outdoors · Apr 24 – May 8
Fall lettuce, spinachSow outdoors · Sep 1 – Sep 15
GarlicPlant cloves · Oct 13 – Nov 17
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 27) 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 06511 came on Apr 2 — about the same time as the 1991–2020 average (Apr 1).

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 New Haven, CT.

Soil in New Haven, CT

The soil mapped at the center of ZIP 06511 is Udorthents — loam, poorly drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureLoama good balance for most vegetables
pH5.6moderately acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter4%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land.

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 06511; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Haven, CT

Summer high82 °Faverage high, July
Winter low23 °Faverage low, January
Hot days6days a year at 90 °F or more
Freezing nights102nights a year at 32 °F or less
Growing degree days3,028base 50 °F — the season’s usable heat
Longest day15 h 10 mindaylight on June 21
Shortest day9 h 11 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation41.8 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 38 °F, low 23 °F 38°23° JanFebruary: average high 40 °F, low 24 °F 40°24° FebMarch: average high 47 °F, low 30 °F 47°30° MarApril: average high 58 °F, low 39 °F 58°39° AprMay: average high 68 °F, low 49 °F 68°49° MayJune: average high 76 °F, low 59 °F 76°59° JunJuly: average high 82 °F, low 66 °F 82°66° JulAugust: average high 81 °F, low 65 °F 81°65° AugSeptember: average high 75 °F, low 57 °F 75°57° SepOctober: average high 64 °F, low 46 °F 64°46° OctNovember: average high 53 °F, low 36 °F 53°36° NovDecember: average high 44 °F, low 29 °F 44°29° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 2.72 in precipitation 2.7 JanFebruary: 2.84 in precipitation 2.8 FebMarch: 3.66 in precipitation 3.7 MarApril: 4.19 in precipitation 4.2 AprMay: 3.54 in precipitation 3.5 MayJune: 3.47 in precipitation 3.5 JunJuly: 3.36 in precipitation 3.4 JulAugust: 3.55 in precipitation 3.5 AugSeptember: 4.03 in precipitation 4.0 SepOctober: 3.78 in precipitation 3.8 OctNovember: 3.12 in precipitation 3.1 NovDecember: 3.53 in precipitation 3.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: New Haven Tweed Airport, CT (4 mi away); precipitation: New Haven Tweed Airport, CT (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

065017a
New Haven, CT · <1 mi
065027a
New Haven, CT · <1 mi
065037a
New Haven, CT · <1 mi
065057a
New Haven, CT · <1 mi
065067a
New Haven, CT · <1 mi
065077a
New Haven, CT · <1 mi
065087a
New Haven, CT · <1 mi
065097a
New Haven, CT · <1 mi

All 28 ZIP codes in New Haven → · Connecticut planting zones →

Questions about 06511

What planting zone is ZIP code 06511?

ZIP code 06511 (New Haven, 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 New Haven, CT?

The median last spring frost (32 °F) near 06511 is April 17; after May 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, New Haven Tweed Airport station.

When is the first frost in New Haven, CT?

The median first fall frost near 06511 is October 27, giving a median frost-free growing season of 193 days.

When should I plant tomatoes in 06511?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 06511 get?

About 41.8 inches of precipitation a year (NOAA 1991–2020 normals, New Haven Tweed Airport station).

How hot do summers get in New Haven, CT?

The average high peaks at 82 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 06511 have?

The USDA soil survey maps Udorthents at the center of ZIP 06511: loam, poorly drained, pH about 5.6 (moderately acidic).

Did spring come early in New Haven, CT in 2026?

Spring leaf-out near 06511 came on Apr 2 in 2026, about the same as the 1991–2020 average (Apr 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in New Haven, CT?

Long-day onions: the longest day near 06511 is 15 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).