Frost Dates for New London, CT
In New London, CT, the average last spring frost is around Apr 16 and the average first fall frost around Oct 28, for a growing season of about 194 days. For frost-tender plants, wait until Apr 30, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Groton New London Airport, CT weather station, 2 miles away, elevation 10 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | Apr 30 | Oct 13 |
| 20% | Apr 25 | Oct 18 |
| 30% | Apr 21 | Oct 22 |
| 40% | Apr 19 | Oct 25 |
| 50% | Apr 16 | Oct 28 |
| 60% | Apr 13 | Oct 31 |
| 70% | Apr 10 | Nov 3 |
| 80% | Apr 8 | Nov 7 |
| 90% | Apr 3 | Nov 12 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | Apr 29 | Oct 16 |
| Frost / freeze (32°F) | Apr 16 | Oct 28 |
| Hard freeze (28°F) | Apr 3 | Nov 9 |
Planting calendar for New London
Transplant Apr 23 – May 7
Transplant Apr 30 – May 14
Transplant Apr 30 – May 14
Transplant Apr 23 – May 7
Sow or transplant Apr 23 – May 7
Sow or transplant Apr 23 – May 7
Sow or transplant Apr 30 – May 14
Sow or transplant Mar 19 – Apr 2
Fall sowing Sep 2 – Sep 30
Fall sowing Sep 2 – Sep 23
Fall sowing Aug 19 – Sep 2
Sow or transplant Mar 19 – Apr 2
Fall sowing Aug 19 – Sep 16
Transplant Apr 2 – Apr 16
Fall sowing Aug 5 – Aug 19
Transplant Mar 26 – Apr 9
Fall sowing Aug 5 – Aug 19
Fall sowing Aug 5 – Aug 19
Fall sowing Sep 16 – Oct 7
Fall sowing Aug 19 – Sep 2
Plant Mar 19 – Apr 2
Based on the average last frost (Apr 16) and first frost (Oct 28). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.