Frost dates for New Haven Tweed Airport, CT
At New Haven Tweed Airport, the median last spring frost (32°F) is Apr 17 and the median first fall frost is Oct 27, for a typical growing season of 193 days. For a 90% chance that the last frost has passed, wait until May 1. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 17Last spring frost (median)50% chance of 32°F after this date
- May 1Safer planting date10% chance of 32°F after this date
- Oct 27First fall frost (median)50% chance of 32°F by this date
- 193 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 17 | Apr 30 | May 12 |
| 32°F | Apr 2 | Apr 17 | May 1 |
| 28°F | Mar 22 | Apr 4 | Apr 18 |
| 24°F | Mar 7 | Mar 25 | Apr 5 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 4 | Oct 15 | Nov 1 |
| 32°F | Oct 11 | Oct 27 | Nov 8 |
| 28°F | Oct 22 | Nov 6 | Nov 21 |
| 24°F | Nov 1 | Nov 19 | Dec 6 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 152 days | 170 days | 189 days |
| 32°F | 174 days | 193 days | 211 days |
| 28°F | 195 days | 215 days | 236 days |
| 24°F | 217 days | 240 days | 263 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 06512 | 7a | 0 to 5°F | 2 km |
| 06519 | 7a | 0 to 5°F | 5 km |
| 06510 | 7a | 0 to 5°F | 6 km |
| 06513 | 7a | 0 to 5°F | 6 km |
| 06516 | 7a | 0 to 5°F | 7 km |
| 06511 | 7a | 0 to 5°F | 7 km |
| 06405 | 7a | 0 to 5°F | 9 km |
| 06515 | 7a | 0 to 5°F | 10 km |
| 06471 | 7a | 0 to 5°F | 12 km |
| 06437 | 7a | 0 to 5°F | 18 km |
| 06443 | 7a | 0 to 5°F | 24 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00014758, at 41.2639, -72.8872, elevation 1 m (3 ft).
- Data quality: Representative (10+ years), 19 years of freeze data.
- Average days per year at or below 32°F: 102.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mount Carmel (16 km)
- Ansonia 1 NE (20 km)
- Bridgeport Sikorsky Mem Airport (23 km)
- Meriden Markham Muni Airport (28 km)
- Danbury (47 km)
- Danbury Muni Airport (51 km)
- Hartford Brainard Field (56 km)
- Stamford 5 N (57 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.