Frost dates for W Thompson Lake, CT
At W Thompson Lake, the median last spring frost (32°F) is May 1 and the median first fall frost is Oct 9, for a typical growing season of 161 days. For a 90% chance that the last frost has passed, wait until May 17. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- May 1Last spring frost (median)50% chance of 32°F after this date
- May 17Safer planting date10% chance of 32°F after this date
- Oct 9First fall frost (median)50% chance of 32°F by this date
- 161 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 | May 1 | May 14 | May 31 |
| 32°F | Apr 20 | May 1 | May 17 |
| 28°F | Apr 5 | Apr 19 | May 2 |
| 24°F | Mar 23 | Apr 6 | Apr 19 |
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 20 | Oct 1 | Oct 13 |
| 32°F | Sep 30 | Oct 9 | Oct 26 |
| 28°F | Oct 6 | Oct 21 | Nov 5 |
| 24°F | Oct 16 | Nov 2 | Nov 20 |
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 | 119 days | 138 days | 155 days |
| 32°F | 140 days | 161 days | 181 days |
| 28°F | 164 days | 184 days | 205 days |
| 24°F | 189 days | 209 days | 231 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 |
|---|---|---|---|
| 06260 | 6b | -5 to 0°F | 5 km |
| 06277 | 6b | -5 to 0°F | 5 km |
| 06255 | 6a | -10 to -5°F | 5 km |
| 06262 | 6a | -10 to -5°F | 9 km |
| 06281 | 6b | -5 to 0°F | 10 km |
| 06259 | 6b | -5 to 0°F | 11 km |
| 06263 | 6b | -5 to 0°F | 12 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 USC00069388, at 41.9442, -71.9031, elevation 110 m (360 ft).
- Data quality: Representative (10+ years), 28 years of freeze data.
- Average days per year at or below 32°F: 156.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Hampton (23 km)
- Staffordville (30 km)
- Storrs (32 km)
- Willimantic Windham Airport (32 km)
- Norwich Public Utility Plant (48 km)
- Hartford Bradley Intl Airport (64 km)
- Hartford Brainard Field (66 km)
- Groton (67 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.