What Growing Zone Is Connecticut In?

Last updated September 6, 2026

USDA hardiness zones

6a to 7a

2023 USDA Plant Hardiness Zone Map

Connecticut spans USDA hardiness zone 6a to 7a across its major population centers, according to the 2023 USDA Plant Hardiness Zone Map. That's a real range, not a single number: where you fall in it depends on where in the state you actually are.

Find your exact zone by ZIP code

Hardiness zone for ZIP 06103 (Hartford)

US ZIP code

Your USDA hardiness zone

Zone 6b

Avg. annual minimum (°F)

-5°F to 0°F

Avg. annual minimum (°C)

-21°C to -18°C

Nearest reference point: Hartford, CT

This is a regional estimate based on the nearest of 826 reference points, each matched to the official 2023 USDA zone map. It’s accurate to within about a half-zone across most of the country, but elevation shifts zones over short distances, so if you’re in mountainous terrain, check the official USDA map for your exact address (see Sources below).

Connecticut's USDA Hardiness Zones

Here's how the zone shifts across Connecticut's major cities:

City	USDA Zone
Litchfield	6a
Hartford	6b
Bridgeport	7a
New Haven	7a

For your exact zone by ZIP code, use the Hardiness Zone Finder, and for what a zone number actually measures (and doesn't), see how zones actually work.

Frost Dates in Connecticut

Frost dates track zone, so they shift across Connecticut the same way the zone number does:

Northwest hills (Litchfield) (zone 6): average last frost Mar 29 - Apr 12, average first frost Oct 18 - Nov 1.
Long Island Sound shoreline (Bridgeport, New Haven) (zone 7): average last frost Mar 18 - Apr 1, average first frost Oct 29 - Nov 12.

These are averages, not guarantees. For your specific frost window, use the Frost Date Calculator. For a full vegetable-by-vegetable planting calendar already calculated from Connecticut's frost dates, see the Connecticut Planting Calendar.

Under the 2023 USDA map, Connecticut splits between two zone bands: a narrow shoreline strip along Long Island Sound (New Haven, Bridgeport, Stamford) reaches the warmer 7a/7b thanks to the Sound's moderating effect, while inland northwest areas (Litchfield County) stay in zone 6.

What Grows Well in Connecticut's Zones

A few real, zone-appropriate picks recommended by UConn Home & Garden Education Center for Connecticut landscapes: not an exhaustive list, but a genuine starting point.

Red maple 'Red Sunset' (Acer rubrum 'Red Sunset')
Littleleaf linden (Tilia cordata)
Thornless honeylocust (Gleditsia triacanthos var. inermis)
Japanese tree lilac (Syringa reticulata)
Washington hawthorn (Crataegus phaenopyrum)

Ready to find your exact zone? Use the Hardiness Zone Finder: enter your ZIP code for a precise match against the 2023 USDA map.

Connecticut Growing Zone FAQ

What growing zone is Connecticut in?

Connecticut spans USDA hardiness zones 6a to 7a on the 2023 USDA Plant Hardiness Zone Map. Litchfield is zone 6a and Hartford is zone 6b; enter your ZIP code in the Hardiness Zone Finder for your exact zone.

What growing zone is Hartford, CT?

Hartford is in USDA hardiness zone 6b on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.

What growing zone is Litchfield, CT?

Litchfield is in USDA hardiness zone 6a on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.

What growing zone is Bridgeport, CT?

Bridgeport is in USDA hardiness zone 7a on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.

What growing zone is New Haven, CT?

New Haven is in USDA hardiness zone 7a on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.

A home yard in coastal New England, with a stone wall, maples and a white clapboard house, planted with red maple 'Red Sunset', littleleaf linden and thornless honeylocust — Plants that suit Connecticut: red maple 'Red Sunset', littleleaf linden and thornless honeylocust. AI-generated image.

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The Spacing & Planting Cheat Sheet

When to start, when to plant, how far apart.

Sources & further reading

Zone and city data checked against the official USDA Plant Hardiness Zone Map. Plant recommendations sourced from UConn Home & Garden Education Center. Climate note sourced from UConn Home & Garden Education Center. For more on how we build and verify reference data across this site, see our methodology page.

Growing zones in nearby states

Gardening near a state line? Zones don't stop at the border:

Or browse all 51 state growing-zone guides.