Frost dates for 06349Groton, CT
The average last spring frost in Groton is April 8 and the average first fall frost is November 2, giving a typical growing season of about 207 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 8
- Average first fall frost
- Nov 2
- Growing season
- 207 days
Safer after Apr 22 (1-in-10 risk)
Possible by Oct 18 (1-in-10 risk)
First frost typically in 2 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 10 · Apr 22 · May 5 | Oct 8 · Oct 21 · Nov 4 | 181 days | 100% |
| Frost / freeze (32°F) | Mar 28 · Apr 8 · Apr 22 | Oct 18 · Nov 2 · Nov 15 | 207 days | 100% |
| Hard freeze (28°F) | Mar 14 · Mar 29 · Apr 7 | Nov 1 · Nov 14 · Dec 1 | 232 days | 100% |
Planting calendar for Groton
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 8 – May 14 |
| Tomatoes | Transplant outdoors | Apr 24 – Jul 13 |
| Peppers | Start seeds indoors | Mar 8 – Apr 8 |
| Peppers | Transplant outdoors | May 8 – Jun 8 |
| Eggplant | Start seeds indoors | Mar 25 – Apr 23 |
| Eggplant | Transplant outdoors | May 8 – Jun 8 |
| Cucumbers | Sow outdoors | May 8 – Jul 23 |
| Summer squash | Sow outdoors | Apr 24 – Jun 8 |
| Winter squash & pumpkins | Sow outdoors | May 8 – Jun 8 |
| Snap beans | Sow outdoors | Apr 24 – Aug 15 |
| Sweet corn | Sow outdoors | Apr 24 – Jul 13 |
| Watermelon & cantaloupe | Sow outdoors | May 8 – Jun 8 |
| Okra | Sow outdoors | May 1 – May 24 |
| Peas | Sow outdoors (spring) | Mar 8 – Apr 23 |
| Potatoes | Plant outdoors (spring) | Mar 8 – May 8 |
| Onions | Start seeds indoors (spring) | Jan 25 – Feb 21 |
| Onions | Transplant outdoors (spring) | Mar 25 – Apr 23 |
| Broccoli | Start seeds indoors (spring) | Feb 18 – Mar 24 |
| Broccoli | Transplant outdoors (spring) | Mar 25 – Apr 23 |
| Broccoli | Start seeds indoors (fall) | Jul 3 – Jul 13 |
| Broccoli | Transplant outdoors (fall) | Aug 2 – Aug 13 |
| Cabbage | Start seeds indoors (spring) | Feb 8 – Mar 8 |
| Cabbage | Transplant outdoors (spring) | Mar 8 – Apr 8 |
| Cabbage | Start seeds indoors (fall) | Jun 23 – Jul 23 |
| Cabbage | Transplant outdoors (fall) | Jul 23 – Aug 23 |
| Leaf lettuce | Sow outdoors (spring) | Mar 8 – May 24 |
| Leaf lettuce | Sow outdoors (fall) | Jul 23 – Sep 8 |
| Spinach | Sow outdoors (spring) | Mar 1 – Apr 14 |
| Spinach | Sow outdoors (fall) | Aug 9 – Sep 13 |
| Radishes | Sow outdoors (spring) | Mar 8 – Apr 28 |
| Radishes | Sow outdoors (fall) | Jul 23 – Sep 23 |
| Kale | Sow outdoors (spring) | Mar 25 – Apr 14 |
| Kale | Sow outdoors (fall) | Jul 16 – Aug 23 |
| Carrots | Sow outdoors (spring) | Apr 8 – May 24 |
| Carrots | Sow outdoors (fall) | Jun 23 – Aug 8 |
| Garlic | Plant outdoors (fall) | Oct 23 – Nov 23 |
Where these dates come from
ZIP code 06349 is matched to the NOAA station Groton, CT, 7 km away, at 40 ft elevation (7 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Groton, CT (used) | 40 ft | Apr 8 | Nov 2 |
| Groton New London Ap, CT | 10 ft | Apr 16 | Oct 28 |
| Norwich Public Utility Plt, CT | 20 ft | Apr 14 | Oct 24 |
| Westerly State Ap, RI | 81 ft | Apr 11 | Oct 31 |
Frost dates near Groton
- Quaker Hill, CT 06375 · last Apr 8, first Nov 2
- Gales Ferry, CT 06335 · last Apr 8, first Nov 2
- Groton, CT 06340 · last Apr 8, first Nov 2
- New London, CT 06320 · last Apr 8, first Nov 2
- Uncasville, CT 06382 · last Apr 14, first Oct 24
- Waterford, CT 06385 · last Apr 16, first Oct 28
- Ledyard, CT 06339 · last Apr 8, first Nov 2
- Montville, CT 06353 · last Apr 14, first Oct 24
Frequently asked questions
- When is the last frost in Groton, CT?
- For ZIP code 06349, the average last spring frost (32°F) is April 8, based on NOAA 1991-2020 climate normals for the Groton, CT weather station. There is a 1-in-10 chance of a frost after April 22.
- When is the first frost in Groton, CT?
- The average first fall frost (32°F) is November 2. There is a 1-in-10 chance of frost by October 18, so tender plants are at risk from that point on.
- How long is the growing season in 06349?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 207 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.