Frost Dates for Norwalk, CT
In Norwalk, CT, the average last spring frost is around Apr 17 and the average first fall frost around Oct 23, for a growing season of about 188 days. For frost-tender plants, wait until May 2, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Stamford 5 N, CT weather station, 7 miles away, elevation 190 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% | May 2 | Oct 8 |
| 20% | Apr 27 | Oct 12 |
| 30% | Apr 23 | Oct 16 |
| 40% | Apr 19 | Oct 19 |
| 50% | Apr 17 | Oct 23 |
| 60% | Apr 14 | Oct 26 |
| 70% | Apr 12 | Oct 29 |
| 80% | Apr 8 | Nov 1 |
| 90% | Apr 3 | Nov 6 |
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 30 | Oct 12 |
| Frost / freeze (32°F) | Apr 17 | Oct 23 |
| Hard freeze (28°F) | Apr 3 | Nov 2 |
Planting calendar for Norwalk
Transplant Apr 24 – May 8
Transplant May 1 – May 15
Transplant May 1 – May 15
Transplant Apr 24 – May 8
Sow or transplant Apr 24 – May 8
Sow or transplant Apr 24 – May 8
Sow or transplant May 1 – May 15
Sow or transplant Mar 20 – Apr 3
Fall sowing Aug 28 – Sep 25
Fall sowing Aug 28 – Sep 18
Fall sowing Aug 14 – Aug 28
Sow or transplant Mar 20 – Apr 3
Fall sowing Aug 14 – Sep 11
Transplant Apr 3 – Apr 17
Fall sowing Jul 31 – Aug 14
Transplant Mar 27 – Apr 10
Fall sowing Jul 31 – Aug 14
Fall sowing Jul 31 – Aug 14
Fall sowing Sep 11 – Oct 2
Fall sowing Aug 14 – Aug 28
Plant Mar 20 – Apr 3
Based on the average last frost (Apr 17) and first frost (Oct 23). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.