Connecticut has 4 USDA hardiness zones from 6a to 7b, with average winter lows from -10°F in the northwestern Litchfield Hills to 10°F along the southwestern shoreline near Norwalk and Greenwich, per the 2023 USDA Plant Hardiness Zone Map.
The northwest Litchfield Hills register zone 6a in Litchfield, Lakeville, Canaan, and Norfolk. Hartford at zones 6b–7a anchors the central interior alongside Bristol 6a–6b and Manchester 6b. The south-central coast reaches New Haven at zones 6b–7a and Bridgeport at zone 7a. The southwestern shoreline runs warmest with Fairfield at zones 7a–7b, Greenwich 7a–7b, Norwalk 7a–7b, Stamford 6b–7b, and a 7b sliver at Byram. New London County’s southeastern coast covers Mystic, Stonington, Groton, and New London at zone 7a, with interior Norwich at zones 6b–7a.
Connecticut’s hardiness zones are also called planting zones, growing zones, gardening zones, plant zones, USDA zones, or climate zones.
Use the city, town, and county lists below, search by ZIP code, or open the interactive Connecticut planting zones map for precise USDA zone locations.
Connecticut Planting Zones by ZIP Code
Connecticut Planting Zones Map
Planting Zones
Planting Zones
USDA Hardiness Zones for Connecticut Counties
| Connecticut Counties | 2023 USDA Hardiness Zones |
|---|---|
| Fairfield County | Zone 6a, 6b, 7a and 7b |
| Hartford County | Zone 6a, 6b and 7a |
| Litchfield County | Zone 6a and 6b |
| Middlesex County | Zone 6b, 7a and 7b |
| New Haven County | Zone 6a, 6b, 7a and 7b |
| New London County | Zone 6b and 7a |
| Tolland County | Zone 6a and 6b |
| Windham County | Zone 6a and 6b |
USDA Hardiness Zones for Connecticut Cities and Towns
| Connecticut City/Town | 2023 USDA Hardiness Zone(s) |
|---|---|
| Ansonia | Zone 6b and 7a |
| Baltic | Zone 6b |
| Bantam | Zone 6a |
| Bethel | Zone 6b |
| Bethlehem Village | Zone 6a and 6b |
| Blue Hills | Zone 6b |
| Branford Center | Zone 7a |
| Bridgeport | Zone 7a |
| Bristol | Zone 6a and 6b |
| Broad Brook | Zone 6b |
| Brooklyn | Zone 6b |
| Byram | Zone 7b |
| Canaan | Zone 6a |
| Cannondale | Zone 6b and 7a |
| Canton Valley | Zone 6a and 6b |
| Cheshire Village | Zone 6b |
| Chester Center | Zone 6b |
| Clinton | Zone 7a |
| Colchester | Zone 6b |
| Collinsville | Zone 6a and 6b |
| Conning Towers Nautilus Park | Zone 7a |
| Cos Cob | Zone 7a and 7b |
| Coventry Lake | Zone 6b |
| Crystal Lake | Zone 6a and 6b |
| Danbury | Zone 6b |
| Deep River Center | Zone 6b and 7a |
| Derby | Zone 6b and 7a |
| Durham | Zone 6b |
| East Brooklyn | Zone 6b |
| East Hampton | Zone 6b |
| East Hartford | Zone 6b and 7a |
| East Haven | Zone 6b, 7a and 7b |
| Essex Village | Zone 6b and 7a |
| Falls Village | Zone 6a |
| Fairfield | Zone 7a and 7b |
| Fenwick | Zone 7a |
| Gales Ferry | Zone 7a |
| Georgetown | Zone 6b |
| Glastonbury Center | Zone 6b and 7a |
| Glenville | Zone 7a and 7b |
| Greenwich | Zone 7a and 7b |
| Groton | Zone 7a |
| Groton Long Point | Zone 7a |
| Guilford Center | Zone 7a |
| Hartford | Zone 6b and 7a |
| Hazardville | Zone 6b |
| Heritage Village | Zone 6b |
| Jewett City | Zone 6b |
| Kensington | Zone 6b |
| Lake Pocotopaug | Zone 6b |
| Lakeville | Zone 6a |
| Litchfield | Zone 6a |
| Long Hill | Zone 7a |
| Madison Center | Zone 7a |
| Manchester | Zone 6b |
| Mansfield Center | Zone 6b |
| Mashantucket | Zone 6b |
| Meriden | Zone 6b |
| Middletown | Zone 6b and 7a |
| Milford | Zone 7a and 7b |
| Moodus | Zone 6b |
| Moosup | Zone 6b |
| Mystic | Zone 7a |
| Naugatuck | Zone 6b |
| New Britain | Zone 6b |
| New Hartford Center | Zone 6a and 6b |
| New Haven | Zone 6b and 7a |
| New London | Zone 7a |
| New Milford | Zone 6b |
| New Preston | Zone 6a |
| Newington | Zone 6b |
| Newtown | Zone 6b |
| Niantic | Zone 7a |
| Noank | Zone 7a |
| Norfolk | Zone 6a |
| North Granby | Zone 6a and 6b |
| North Grosvenor Dale | Zone 6a and 6b |
| North Haven | Zone 6b and 7a |
| Northwest Harwinton | Zone 6a |
| Norwalk | Zone 7a and 7b |
| Norwich | Zone 6b and 7a |
| Oakville | Zone 6b |
| Old Greenwich | Zone 7a and 7b |
| Old Mystic | Zone 7a |
| Old Saybrook Center | Zone 7a |
| Orange | Zone 7a |
| Oxoboxo River | Zone 6b and 7a |
| Pawcatuck | Zone 7a |
| Pemberwick | Zone 7a and 7b |
| Plainfield Village | Zone 6b |
| Poquonock Bridge | Zone 7a |
| Portland | Zone 6b and 7a |
| Quinebaug | Zone 6a and 6b |
| Ridgefield | Zone 6b |
| Riverside | Zone 7a and 7b |
| Rockville | Zone 6b |
| Salmon Brook | Zone 6b |
| Saybrook Manor | Zone 7a |
| Sharon | Zone 6a |
| Shelton | Zone 6b and 7a |
| Sherwood Manor | Zone 6b |
| Simsbury Center | Zone 6b |
| Somers | Zone 6b |
| South Coventry | Zone 6b |
| South Windham | Zone 6b |
| South Woodstock | Zone 6a and 6b |
| Southport | Zone 7a |
| Southwood Acres | Zone 6b |
| Stafford Springs | Zone 6a and 6b |
| Stamford | Zone 6b, 7a and 7b |
| Stonington | Zone 7a |
| Storrs | Zone 6b |
| Suffield Depot | Zone 6b |
| Tariffville | Zone 6b |
| Terramuggus | Zone 6b |
| Thomaston | Zone 6a and 6b |
| Thompsonville | Zone 6b |
| Torrington | Zone 6a |
| Wallingford Center | Zone 6b |
| Waterbury | Zone 6a and 6b |
| Waterford | Zone 7a |
| Watertown | Zone 6b |
| Wauregan | Zone 6b |
| Weatogue | Zone 6b |
| West Hartford | Zone 6a and 6b |
| West Haven | Zone 7a |
| West Simsbury | Zone 6a and 6b |
| Westbrook Center | Zone 7a |
| Wethersfield | Zone 6b and 7a |
| Willimantic | Zone 6b |
| Wilton Center | Zone 7a |
| Windsor Locks | Zone 6b |
| Winsted | Zone 6a |
| Woodbury Center | Zone 6b |
| Woodmont | Zone 7a |