Connecticut frost dates
Across 23 NOAA climate stations in Connecticut, the median last spring frost (32°F) ranges from Apr 5 at Bridgeport Sikorsky Mem AP to May 11 at Falls Village; the typical station sees its last frost around Apr 25 and its first fall frost around Oct 17.
“Median” dates have a 50% chance of a later spring frost or an earlier fall frost. “10% risk” dates are the safer choice for tender plants: only 1 year in 10 has frost beyond them. Source: NOAA NCEI 1991–2020 Climate Normals. Elevation matters: within a state, frost dates can differ by a month or more between valleys and hills.
| Station | Elevation | Last frost (median) | Last frost (10% risk) | First frost (median) | First frost (10% risk) | Growing season |
|---|---|---|---|---|---|---|
| Ansonia 1 Ne | 136 ft | Apr 25 | May 10 | Oct 17 | Oct 4 | 175 days |
| Bakersville | 686 ft | May 8 | May 22 | Oct 5 | Sep 25 | 151 days |
| Barkhamsted | 710 ft | Apr 30 | May 15 | Oct 17 | Oct 4 | 168 days |
| Bridgeport Sikorsky Mem AP | 5 ft | Apr 5 | Apr 17 | Nov 6 | Oct 25 | 216 days |
| Burlington | 505 ft | Apr 25 | May 10 | Oct 18 | Oct 4 | 172 days |
| Danbury | 405 ft | Apr 20 | May 6 | Oct 20 | Oct 5 | 181 days |
| Danbury Muni AP | 457 ft | May 1 | May 16 | Oct 14 | Oct 1 | 166 days |
| Falls Village | 550 ft | May 11 | May 27 | Oct 4 | Sep 21 | 146 days |
| Groton | 40 ft | Apr 8 | Apr 22 | Nov 2 | Oct 18 | 207 days |
| Groton New London AP | 10 ft | Apr 16 | Apr 30 | Oct 28 | Oct 13 | 194 days |
| Hampton | 490 ft | Apr 30 | May 11 | Oct 15 | Oct 1 | 167 days |
| Hartford Bradley Intl AP | 190 ft | Apr 21 | May 6 | Oct 16 | Oct 3 | 177 days |
| Hartford Brainard Fld | 19 ft | Apr 17 | May 1 | Oct 26 | Oct 12 | 191 days |
| Meriden Markham Muni AP | 103 ft | Apr 26 | May 9 | Oct 16 | Oct 4 | 175 days |
| Mt Carmel | 180 ft | Apr 18 | May 3 | Oct 26 | Oct 11 | 191 days |
| New Haven Tweed AP | 3 ft | Apr 17 | May 1 | Oct 27 | Oct 11 | 193 days |
| Norfolk 2 Sw | 1,340 ft | May 3 | May 17 | Oct 11 | Oct 1 | 161 days |
| Norwich Public Utility Plt | 20 ft | Apr 14 | Apr 30 | Oct 24 | Oct 9 | 192 days |
| Staffordville | 736 ft | May 7 | May 21 | Oct 12 | Oct 1 | 159 days |
| Stamford 5 N | 190 ft | Apr 17 | May 2 | Oct 23 | Oct 8 | 188 days |
| Storrs | 665 ft | Apr 19 | May 3 | Oct 22 | Oct 6 | 186 days |
| W Thompson Lake | 360 ft | May 1 | May 17 | Oct 9 | Sep 30 | 161 days |
| Willimantic Windham AP | 247 ft | Apr 28 | May 11 | Oct 13 | Oct 2 | 167 days |
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