Connecticut frost dates
The typical last spring frost ranges from Apr 5 in Bridgeport to Apr 26 in Waterbury.
6 of the 6 Connecticut cities listed have typical frost dates. The longest frost-free season is 216 days in Bridgeport; the shortest is 175 days in Waterbury. For a single address, look up your ZIP code: rural ZIPs use their nearest suitable station.
| City | Last spring frost | 1 in 10 after | First fall frost | 1 in 10 before | Hard freeze (28°F) | Season |
|---|---|---|---|---|---|---|
| Bridgeport | Apr 5 | Apr 17 | Nov 6 | Oct 25 | Mar 26 / Nov 19 | 216 days |
| Hartford | Apr 17 | May 1 | Oct 26 | Oct 12 | Apr 3 / Nov 5 | 191 days |
| Mystic | Apr 16 | Apr 30 | Oct 28 | Oct 13 | Apr 3 / Nov 9 | 194 days |
| New Haven | Apr 17 | May 1 | Oct 27 | Oct 11 | Apr 4 / Nov 6 | 193 days |
| Stamford | Apr 12 | Apr 27 | Oct 31 | Oct 15 | Apr 1 / Nov 13 | 200 days |
| Waterbury | Apr 26 | May 9 | Oct 16 | Oct 4 | Apr 10 / Oct 30 | 175 days |
Reading the table: Hartford
In Hartford, the last spring frost typically comes around Apr 17: in half of years it is earlier, in half later. In 1 year in 10 it comes after May 1, 14 days later, so tender plants set out after that date have a 90% chance of escaping frost. In fall, the first frost typically arrives around Oct 26, and in 1 year in 10 before Oct 12. Hard freezes (28°F) usually end earlier in spring and start later in fall: around Apr 3 and Nov 5 in Hartford.
Frost dates at more Connecticut weather stations
NOAA stations across Connecticut used by our ZIP code lookup, named for the town they are in.
| Station | Elevation | Last spring frost | First fall frost |
|---|---|---|---|
| Bakersville | 686 ft | May 8 (1 in 10 after May 22) | Oct 5 (before Sep 25) |
| Burlington | 505 ft | Apr 25 (1 in 10 after May 10) | Oct 18 (before Oct 4) |
| Danbury | 405 ft | Apr 20 (1 in 10 after May 6) | Oct 20 (before Oct 5) |
| Danbury Muni Airport | 457 ft | May 1 (1 in 10 after May 16) | Oct 14 (before Oct 1) |
| Falls Village | 550 ft | May 11 (1 in 10 after May 27) | Oct 4 (before Sep 21) |
| Hartford Bradley Intl Airport | 190 ft | Apr 21 (1 in 10 after May 6) | Oct 16 (before Oct 3) |
| Mt Carmel | 180 ft | Apr 18 (1 in 10 after May 3) | Oct 26 (before Oct 11) |
| Norfolk 2 Sw | 1,340 ft | May 3 (1 in 10 after May 17) | Oct 11 (before Oct 1) |
| Norwich Public Utility Plt | 20 ft | Apr 14 (1 in 10 after Apr 30) | Oct 24 (before Oct 9) |
| Staffordville | 736 ft | May 7 (1 in 10 after May 21) | Oct 12 (before Oct 1) |
| Stamford 5 N | 190 ft | Apr 17 (1 in 10 after May 2) | Oct 23 (before Oct 8) |
| Storrs | 665 ft | Apr 19 (1 in 10 after May 3) | Oct 22 (before Oct 6) |
| W Thompson Lake | 360 ft | May 1 (1 in 10 after May 17) | Oct 9 (before Sep 30) |
| Willimantic Windham Airport | 247 ft | Apr 28 (1 in 10 after May 11) | Oct 13 (before Oct 2) |
32°F dates from NOAA 1991-2020 freeze probabilities for each city's station. "1 in 10 after": a 10% chance of a later spring frost (planting is 90% safe after it). How to read frost dates.