Frost dates in Connecticut
Across Connecticut's 23 NOAA stations with a frost every year, the typical last spring frost ranges from April 5 at Bridgeport Sikorsky Mem Airport (at sea level) to May 11 at Falls Village (550 feet above sea level). The middle station's date is April 25.
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Last frost across Connecticut
The frost-free season runs from 146 days at Falls Village to 216 days at Bridgeport Sikorsky Mem Airport.
These are typical dates: in half of springs the last frost comes later. Each place's page, and each ZIP code lookup, also gives the late-year date, after which only 1 spring in 10 has a frost. That's the safer date for tender plants.
Frost dates for Connecticut's larger places
| Place | Last spring frost | First fall frost | Season | Zone |
|---|---|---|---|---|
| Bridgeport | April 5 | November 6 | 216 days | 7a |
| Hartford | April 17 | October 26 | 191 days | 6b |
| New Haven | April 17 | October 27 | 193 days | 7a |
| Stamford | April 17 | October 23 | 188 days | 7a |
| Waterbury | April 26 | October 16 | 175 days | 6b |
Typical (1-in-2) dates. Each place's page has the early and late years, a planting calendar and a printable planner. Zones are for the ZIP code nearest each place's center.
Hardiness zones in Connecticut
Connecticut's 418 ZIP codes in the USDA list fall in zones 6a to 7b: 6a (12 percent), 6b (60 percent), 7a (27 percent) and 7b (1 percent). Compared with the 2012 map, 46 percent of them moved to a warmer half zone and 54 percent stayed the same.
A hardiness zone is about the coldest night of winter, which decides which shrubs, trees and perennials survive. Frost dates are about spring and fall, which decide when to plant. You need both. Read more about what the zones mean and what changed in 2023.
Every NOAA station in Connecticut
All 23 stations in Connecticut with frost statistics in NOAA's 1991 to 2020 normals, from A to Z. Station names are usually a town, an airport, or a distance and direction from a town. Find one near you and at a similar elevation.
| Station | Elevation (feet) | Last spring frost | First fall frost | Season (days) |
|---|---|---|---|---|
| Ansonia 1 NE | 140 | April 25 | October 17 | 175 |
| Bakersville | 690 | May 8 | October 5 | 151 |
| Barkhamsted | 710 | April 30 | October 17 | 168 |
| Bridgeport Sikorsky Mem Airport | 10 | April 5 | November 6 | 216 |
| Burlington | 510 | April 25 | October 18 | 172 |
| Danbury | 400 | April 20 | October 20 | 181 |
| Danbury Municipal Airport | 460 | May 1 | October 14 | 166 |
| Falls Village | 550 | May 11 | October 4 | 146 |
| Groton | 40 | April 8 | November 2 | 207 |
| Groton New London Airport | 10 | April 16 | October 28 | 194 |
| Hampton | 490 | April 30 | October 15 | 167 |
| Hartford Bradley International Airport | 190 | April 21 | October 16 | 177 |
| Hartford Brainard Field | 20 | April 17 | October 26 | 191 |
| Meriden Markham Municipal Airport | 100 | April 26 | October 16 | 175 |
| Mount Carmel | 180 | April 18 | October 26 | 191 |
| New Haven Tweed Airport | 0 | April 17 | October 27 | 193 |
| Norfolk 2 SW | 1,340 | May 3 | October 11 | 161 |
| Norwich Public Utility Plant | 20 | April 14 | October 24 | 192 |
| Staffordville | 730 | May 7 | October 12 | 159 |
| Stamford 5 N | 190 | April 17 | October 23 | 188 |
| Storrs | 670 | April 19 | October 22 | 186 |
| W Thompson Lake | 360 | May 1 | October 9 | 161 |
| Willimantic Windham Airport | 250 | April 28 | October 13 | 167 |
Typical (1-in-2) dates at 32°F. For the early and late years, and a planting calendar built from your own dates, look up your ZIP code.