Connecticut Planting Zones by City and ZIP Code
Connecticut runs from zones 6a to 7b; 60% of its ZIPs are 6b, Hartford is 6b and New Haven is 7a.
Connecticut runs from zones 6a to 7b
The coldest night of the winter averages -10°F to -5°F in the coldest of Connecticut’s ZIP codes and 5°F to 10°F in the warmest. Most of the state is zone 6b.
Planting zones of Connecticut cities
| City | Zone | Coldest night, on average | Since 2012 |
|---|---|---|---|
| Hartford06103 | 6b | -5°F to 0°F | same as 2012 |
| New Haven06510 | 7a | 0°F to 5°F | same as 2012 |
| Bridgeport06604 | 7a | 0°F to 5°F | same as 2012 |
| Stamford06901 | 7a | 0°F to 5°F | same as 2012 |
| Norwich06360 | 6b | -5°F to 0°F | same as 2012 |
| Torrington06790 | 6a | -10°F to -5°F | same as 2012 |
Tap a ZIP for that address’s frost dates and this month’s jobs.
Find your zone anywhere in Connecticut
A ZIP code or a town gives you its zone, how it moved since 2012, the frost dates at the nearest NOAA station, and the jobs for this month timed from them.
What to plant in Connecticut this month
The calendar for each of Connecticut's main zones, from vegetables to pruning and winter protection, each job tied to the extension page it comes from. Pick a month, or read the whole year below it.
Timed from the median frost dates of the 13 NOAA stations in Connecticut’s zone 6b: last spring frost Apr 25, first fall frost Oct 16. Your own ZIP’s frost dates move every window, so the ZIP tool times them for you.
Pick a month above to see every job in it.
The year at a glance
- Start vegetable seeds indoorsJan to Apr
- Sow vegetables in the gardenMar to May
- Sow the fall vegetable gardenJun to Aug
- Set out transplantsMar to May
- Plant trees and shrubsMar 14 to May 9 and Oct 2 to Nov 20
- Plant garlicOct 2 to Nov 6
- Plant tulips and other spring bulbsOct 23 to Oct 30
- Divide fall-blooming perennialsApr 4 to May 16
- Divide spring and summer-blooming perennialsSep 4 to Oct 16
- Prune trees and summer-flowering shrubs while dormantFeb 14 to Mar 28
- Prune spring-flowering shrubs after they bloomApr 11 to Jun 6
- Water evergreens and new plantings until the ground freezesSep 18 to Nov 27
- Mulch perennial crowns once the ground freezesNov 27 to Dec 11
- Pull back the winter mulchMar 7 to Mar 21
- Put hardware cloth around young tree trunksOct 16 to Nov 27
- Dig and store dahlia and gladiolusOct 16 to Oct 23
- Cut back perennials after a hard freezeOct 23 to Nov 20
What changed in Connecticut since 2012
Every ZIP on both mapsCompared ZIP by ZIP from the 2023 and 2012 USDA tables; 419 Connecticut ZIP codes appear in both.
Why Connecticut’s zones moved
Every city above is in the same half zone it was on the 2012 map.
The USDA explains the national picture: “When compared to the 2012 map, the 2023 version reveals that about half of the country shifted to the next warmer half zone, and the other half of the country remained in the same half zone.” The new map uses 1991 to 2020 and more than 13,000 weather stations, so it draws Connecticut’s hills, valleys and cities more finely than the 2012 map did.
A warmer zone changes which perennials and shrubs come through the winter, not when the garden gets planted; that still follows the frost dates.
Frost dates and seed starting in Connecticut
Connecticut planting zone questions
Planting zones by state
Sources. USDA Plant Hardiness Zone Map, ZIP code tables (2023 and 2012), PRISM Climate Group, Oregon State University; USDA Plant Hardiness Zone Map; USDA Unveils Updated Plant Hardiness Zone Map (USDA Agricultural Research Service, November 15, 2023); NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal, by station (v1.0.1); NC State Extension Gardener Plant Toolbox. Zones are read from the PRISM ZIP code tables, read Oct 9, 2026; a ZIP code’s zone is the zone at its center. The calendar’s extension sources are listed on the planting zones page and under each job.