USDA hardiness zones — 2023 map
Connecticut hardiness zones — USDA planting zone map + what to grow
Zones 5b-7b · most of Connecticut is zone 6b · Northeast region
ConnecticutUSDA zone range & map
On the 2023 USDA Plant Hardiness Zone Map, Connecticut spans zones 5b-7b. The map shades the state from the northwest hills near Litchfield (zone 5b) through to the Long Island Sound shoreline (zone 7b). The single most common half-zone across the populated state is zone 6b — that is the figure to use if you only remember one number for Connecticut. Connecticut has a classic four-season New England climate with a coastal strip a full zone milder than the inland hills.
| USDA zone range | Zones 5b-7b |
|---|---|
| Most common zone | Zone 6b |
| Coldest area | the northwest hills near Litchfield (zone 5b) |
| Warmest area | the Long Island Sound shoreline (zone 7b) |
| Average last spring frost | late April |
| Average first fall frost | mid-October |
Source: USDA 2023 Plant Hardiness Zone Map (1991-2020 normals). Frost averages: NOAA/NCEI 1991-2020 climate normals. Local ZIP-level zones and frost dates can differ from these statewide figures.
Connecticut hardiness zones by major city
Zones shift across Connecticut with elevation and distance from the coast. Here is the 2023 USDA half-zone for the largest cities:
| City | USDA zone |
|---|---|
| Hartford | Zone 6b |
| New Haven | Zone 7a |
| Bridgeport | Zone 7a |
| Stamford | Zone 7a |
Need your exact zone? Run the ZIP-code zone finder for a precise half-zone and frost dates for your address.
ZIP-code zones in Connecticut
Statewide ranges hide a lot. Tap your area for its exact USDA half-zone, last and first frost dates, and what to plant now:
- Enfield 06082 — Zone 6b
- Hartford 06103 — Zone 6b
- Hartford (South End) 06106 — Zone 6b
- Norwich 06360 — Zone 6b
- New Haven 06510 — Zone 7a
- New Haven (East Rock) 06511 — Zone 7a
- Bridgeport 06606 — Zone 7a
- Fairfield 06824 — Zone 7a
- New Canaan 06840 — Zone 6b
- Stamford 06901 — Zone 7a
What Connecticut's zone range means for planting
Your hardiness zone tells you which perennials, shrubs, and trees will survive a typical Connecticut winter, and it anchors when tender crops can go outside. Because Connecticut spans 5b-7b, two gardeners in the same state can have very different planting calendars.
- Pick perennials hardy to your local zone. Across most of Connecticut that means at least zone 6b; gardeners in the northwest hills near Litchfield (zone 5b) should choose hardier plants.
- Anchor tender crops to your frost dates. With a last spring frost around late April and first fall frost around mid-October, set out tomatoes, peppers, and basil after the last frost and protect them before the first.
- Adjust for your microclimate. Urban heat, a south-facing slope, or a cold valley pocket can shift your effective zone and frost dates by a half-zone or more from the statewide figure.
Find your exact zone in Connecticut
The 5b-7b range is statewide. Growli pins your hardiness zone and frost dates to your exact ZIP code and sends a push notification before any forecast frost night for your saved location.
Frequently asked questions
What hardiness zone is Connecticut?
Connecticut spans USDA hardiness zones 5b-7b on the 2023 USDA Plant Hardiness Zone Map. The most common zone — covering the largest share of the populated state — is zone 6b. The coldest areas are the northwest hills near Litchfield (zone 5b) and the warmest are the Long Island Sound shoreline (zone 7b).
When is the last frost in Connecticut?
Across most of Connecticut the average last spring frost falls around late April and the first fall frost around mid-October. These are statewide averages — colder, higher areas run later in spring and earlier in fall, so check a ZIP-level estimate for your exact spot.
What grows well in Connecticut?
Connecticut has a classic four-season New England climate with a coastal strip a full zone milder than the inland hills. Match plants to your local half-zone within the 5b-7b range: choose varieties hardy to at least zone 6b for reliable overwintering, and time tender crops around your local frost dates. The zone 6 planting guide lists vegetables, fruit, and ornamentals suited to most of the state.
Why does Connecticut have more than one hardiness zone?
Hardiness zones track the average annual coldest temperature, which changes with latitude, elevation, distance from water, and urban heat. That is why Connecticut ranges from the northwest hills near Litchfield (zone 5b) to the Long Island Sound shoreline (zone 7b) — a span of 5b-7b — even though it is a single state.
Did Connecticut's hardiness zone change in 2023?
The USDA updated the Plant Hardiness Zone Map in November 2023 using 1991-2020 climate data. About half the country, including parts of Connecticut, shifted to the next warmer half-zone versus the 2012 map. The 5b-7b range here reflects the current 2023 map. Always confirm your address against the official USDA map for plant-survival decisions.