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

Planting zone for 06504 — New Haven, CT

ZIP code 06504 (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 18 and the first fall frost October 26.

Where ZIP 06504 is

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 18
First frostOct 26
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 18median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 26median — 10% chance by Oct 11
Growing season191 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around November 6.

From the NOAA station Mt Carmel, CT — 3 miles away, elevation 180 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 06504

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 7 – Mar 21
SpinachSow outdoors · Mar 7 – Mar 28
Broccoli, cabbageStart indoors · Feb 7 – Feb 21
Broccoli, cabbageTransplant · Mar 28 – Apr 11
Onion setsPlant outdoors · Mar 21 – Apr 4
PotatoesPlant outdoors · Mar 28 – Apr 11
LettuceSow outdoors · Mar 21 – Apr 4
Carrots, beetsSow outdoors · Mar 28 – Apr 11
TomatoesStart indoors · Feb 21 – Mar 7
TomatoesTransplant · Apr 25 – May 9
Peppers, eggplantStart indoors · Feb 7 – Feb 21
Peppers, eggplantTransplant · May 2 – May 16
BeansSow outdoors · Apr 25 – May 9
Sweet cornSow outdoors · Apr 25 – May 9
Cucumbers, squashSow outdoors · Apr 25 – May 9
Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14
GarlicPlant cloves · Oct 12 – Nov 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 18) and first fall frost (Oct 26) 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 06504 came on Apr 3 — about the same time as the 1991–2020 average (Apr 3).

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 06504 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 06504; 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 high85 °Faverage high, July
Winter low20 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights123nights a year at 32 °F or less
Growing degree days3,078base 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)
Precipitation50.4 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 38 °F, low 20 °F 38°20° JanFebruary: average high 41 °F, low 22 °F 41°22° FebMarch: average high 48 °F, low 28 °F 48°28° MarApril: average high 61 °F, low 38 °F 61°38° AprMay: average high 71 °F, low 48 °F 71°48° MayJune: average high 79 °F, low 58 °F 79°58° JunJuly: average high 85 °F, low 64 °F 85°64° JulAugust: average high 84 °F, low 62 °F 84°62° AugSeptember: average high 76 °F, low 55 °F 76°55° SepOctober: average high 64 °F, low 43 °F 64°43° OctNovember: average high 53 °F, low 34 °F 53°34° NovDecember: average high 42 °F, low 27 °F 42°27° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.60 in precipitation 3.6 JanFebruary: 3.46 in precipitation 3.5 FebMarch: 4.43 in precipitation 4.4 MarApril: 4.66 in precipitation 4.7 AprMay: 3.68 in precipitation 3.7 MayJune: 4.90 in precipitation 4.9 JunJuly: 3.81 in precipitation 3.8 JulAugust: 3.77 in precipitation 3.8 AugSeptember: 4.33 in precipitation 4.3 SepOctober: 4.91 in precipitation 4.9 OctNovember: 4.35 in precipitation 4.3 NovDecember: 4.51 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mt Carmel, CT (3 mi away); precipitation: Mt Carmel, CT (3 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.

064086b
Cheshire, CT · <1 mi
064936b
Wallingford, CT · <1 mi
064946b
Wallingford, CT · <1 mi
065377a
New Haven, CT · <1 mi
065387a
New Haven, CT · <1 mi
065146b
Hamden, CT · 1 mi
065177a
Hamden, CT · 2 mi
064956b
Wallingford, CT · 3 mi

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

Questions about 06504

What planting zone is ZIP code 06504?

ZIP code 06504 (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 06504 is April 18; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mt Carmel station.

When is the first frost in New Haven, CT?

The median first fall frost near 06504 is October 26, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 06504?

Start tomato seeds indoors around Feb 21 – Mar 7 and set transplants outside around Apr 25 – May 9, one to three weeks after the median last frost.

How much rain and snow does 06504 get?

About 50.4 inches of precipitation a year (NOAA 1991–2020 normals, Mt Carmel station).

How hot do summers get in New Haven, CT?

The average high peaks at 85 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 06504 have?

The USDA soil survey maps Udorthents at the center of ZIP 06504: loam, poorly drained, pH about 5.6 (moderately acidic).

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

Spring leaf-out near 06504 came on Apr 3 in 2026, about the same as the 1991–2020 average (Apr 3), 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 06504 is 15 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).