Frost dates for Ansonia 1 NE, CT
At Ansonia 1 NE, the median last spring frost (32°F) is Apr 25 and the median first fall frost is Oct 17, for a typical growing season of 175 days. For a 90% chance that the last frost has passed, wait until May 10. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 25Last spring frost (median)50% chance of 32°F after this date
- May 10Safer planting date10% chance of 32°F after this date
- Oct 17First fall frost (median)50% chance of 32°F by this date
- 175 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 24 | May 8 | May 22 |
| 32°F | Apr 11 | Apr 25 | May 10 |
| 28°F | Mar 30 | Apr 10 | Apr 27 |
| 24°F | Mar 15 | Mar 30 | Apr 10 |
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 | Sep 27 | Oct 7 | Oct 21 |
| 32°F | Oct 4 | Oct 17 | Nov 1 |
| 28°F | Oct 14 | Oct 30 | Nov 13 |
| 24°F | Oct 26 | Nov 12 | Nov 30 |
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 | 132 days | 151 days | 172 days |
| 32°F | 153 days | 175 days | 197 days |
| 28°F | 179 days | 202 days | 220 days |
| 24°F | 205 days | 225 days | 247 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 |
|---|---|---|---|
| 06401 | 6b | -5 to 0°F | 2 km |
| 06418 | 6b | -5 to 0°F | 3 km |
| 06483 | 6b | -5 to 0°F | 4 km |
| 06484 | 6b | -5 to 0°F | 6 km |
| 06525 | 6b | -5 to 0°F | 8 km |
| 06477 | 7a | 0 to 5°F | 9 km |
| 06468 | 6b | -5 to 0°F | 11 km |
| 06403 | 6b | -5 to 0°F | 11 km |
| 06478 | 6b | -5 to 0°F | 12 km |
| 06611 | 7a | 0 to 5°F | 13 km |
| 06482 | 6b | -5 to 0°F | 14 km |
| 06762 | 6b | -5 to 0°F | 20 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 USC00060128, at 41.3492, -73.0917, elevation 42 m (136 ft).
- Data quality: Estimated from nearby stations (2+ years), 7 years of freeze data.
- Average days per year at or below 32°F: 130.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mount Carmel (17 km)
- New Haven Tweed Airport (20 km)
- Bridgeport Sikorsky Mem Airport (21 km)
- Danbury (28 km)
- Meriden Markham Muni Airport (28 km)
- Danbury Muni Airport (33 km)
- Stamford 5 N (46 km)
- Burlington (51 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.