Frost dates for 06518Hamden, CT
The average last spring frost in Hamden is April 18 and the average first fall frost is October 26, giving a typical growing season of about 191 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 26
- Growing season
- 191 days
Safer after May 3 (1-in-10 risk)
Possible by Oct 11 (1-in-10 risk)
Last frost typically in 168 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 18 · May 1 · May 16 | Oct 2 · Oct 15 · Oct 30 | 166 days | 100% |
| Frost / freeze (32°F) | Apr 5 · Apr 18 · May 3 | Oct 11 · Oct 26 · Nov 9 | 191 days | 100% |
| Hard freeze (28°F) | Mar 23 · Apr 5 · Apr 19 | Oct 22 · Nov 6 · Nov 22 | 214 days | 100% |
Planting calendar for Hamden
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 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jul 6 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 16 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 8 |
| Sweet corn | Sow outdoors | May 4 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 06518 is matched to the NOAA station Mt Carmel, CT, 0.7 km away, at 180 ft elevation (40 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mt Carmel, CT (used) | 180 ft | Apr 18 | Oct 26 |
| Meriden Markham Muni Ap, CT | 103 ft | Apr 26 | Oct 16 |
| New Haven Tweed Ap, CT | 3 ft | Apr 17 | Oct 27 |
| Ansonia 1 Ne, CT | 136 ft | Apr 25 | Oct 17 |
Frost dates near Hamden
- Wallingford, CT 06495 · last Apr 17, first Oct 27
- Cheshire, CT 06408 · last Apr 17, first Oct 27
- New Haven, CT 06504 · last Apr 17, first Oct 27
- North Haven, CT 06473 · last Apr 17, first Oct 27
- Hamden, CT 06514 · last Apr 17, first Oct 27
- Bethany, CT 06524 · last Apr 26, first Oct 16
- Northford, CT 06472 · last Apr 26, first Oct 16
- Prospect, CT 06712 · last May 8, first Oct 5
Frequently asked questions
- When is the last frost in Hamden, CT?
- For ZIP code 06518, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Mt Carmel, CT weather station. There is a 1-in-10 chance of a frost after May 3.
- When is the first frost in Hamden, CT?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 11, so tender plants are at risk from that point on.
- How long is the growing season in 06518?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 191 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.