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Will it freeze in Groton in the next 7 nights?
No overnight lows at or below 32°F are forecast in Groton during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 62°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
1 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 62°F Above 36°F · Light Rain Likely then Showers And Thunderstorms
- Fri, Nov 6 58°F Above 36°F · Rain
- Sat, Nov 7 48°F Above 36°F · Chance Light Rain
- Sun, Nov 8 42°F Above 36°F · Mostly Clear
- Mon, Nov 9 40°F Above 36°F · Mostly Clear
- Tue, Nov 10 42°F Above 36°F · Mostly Clear
- Wed, Nov 11 36°F Frost possible · Mostly Clear
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Groton
The median first fall hard-freeze date (28°F) is November 9, from NOAA’s 1991–2020 Climate Normals at Groton New London Airport. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 18 · Apr 29 · May 11 | Oct 5 · Oct 16 · Oct 31 | 170 days |
| 32°F freeze | Apr 3 · Apr 16 · Apr 30 | Oct 13 · Oct 28 · Nov 12 | 194 days |
| 28°F hard freeze | Mar 19 · Apr 3 · Apr 17 | Oct 25 · Nov 9 · Nov 27 | 220 days |
Average high temperature by month
1991–2020 normals at Groton New London Airport
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Groton, CT come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Groton New London Airport (station USW00014707, elevation 10 ft), 0.9 mi from Groton. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Groton
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| New London, CT | 1.9 mi | Apr 16 | Oct 28 |
| Norwich, CT | 16 mi | Apr 14 | Oct 24 |
| Middletown, CT | 34 mi | Apr 26 | Oct 16 |
| Newport, RI | 40 mi | Apr 7 | Nov 13 |
| Meriden, CT | 40 mi | Apr 26 | Oct 16 |
| Warwick, RI | 42 mi | Apr 11 | Oct 30 |
| Cranston, RI | 43 mi | Apr 11 | Oct 30 |
| Hartford, CT | 44 mi | Apr 17 | Oct 26 |
| New Britain, CT | 45 mi | Apr 17 | Oct 26 |
| New Haven, CT | 45 mi | Apr 17 | Oct 27 |
Frequently asked questions
When is the last frost in Groton?
On average, the last spring frost (32°F) in Groton is around April 16. In about 1 year in 10 it comes after April 30, and in 9 years in 10 it comes after April 3.
When is the first frost in Groton?
The first fall frost (32°F) usually arrives around October 28. There’s a 10% chance of a freeze by October 13 and a 90% chance by November 12.
Can it frost in Groton after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 29.
What growing zone is Groton?
Groton is in USDA Plant Hardiness Zone 7a (average annual extreme minimum temperature 0 to 5°F), based on the 2023 USDA map for ZIP code 06340. See growing zones in Connecticut.
More: all Connecticut frost dates · Connecticut growing zones · frost vs. freeze