Frost dates for 06103Hartford, CT
The average last spring frost in Hartford is April 17 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 17
- Average first fall frost
- Oct 26
- Growing season
- 191 days
Safer after May 1 (1-in-10 risk)
Possible by Oct 12 (1-in-10 risk)
Last frost typically in 167 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 17 · Apr 30 · May 14 | Oct 2 · Oct 14 · Oct 29 | 167 days | 100% |
| Frost / freeze (32°F) | Apr 1 · Apr 17 · May 1 | Oct 12 · Oct 26 · Nov 7 | 191 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 3 · Apr 21 | Oct 22 · Nov 5 · Nov 20 | 216 days | 100% |
Planting calendar for Hartford
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 17 – May 23 |
| Tomatoes | Transplant outdoors | May 3 – Jul 6 |
| Peppers | Start seeds indoors | Mar 17 – Apr 17 |
| Peppers | Transplant outdoors | May 17 – Jun 17 |
| Eggplant | Start seeds indoors | Apr 3 – May 2 |
| Eggplant | Transplant outdoors | May 17 – Jun 17 |
| Cucumbers | Sow outdoors | May 17 – Jul 16 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 8 |
| Sweet corn | Sow outdoors | May 3 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 17 – Jun 17 |
| Okra | Sow outdoors | May 10 – Jun 2 |
| Peas | Sow outdoors (spring) | Mar 17 – May 2 |
| Potatoes | Plant outdoors (spring) | Mar 17 – May 17 |
| Onions | Start seeds indoors (spring) | Feb 3 – Mar 2 |
| Onions | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (spring) | Feb 27 – Apr 2 |
| Broccoli | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 06103 is matched to the NOAA station Hartford Brainard Fld, CT, 4 km away, at 19 ft elevation (30 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hartford Brainard Fld, CT (used) | 19 ft | Apr 17 | Oct 26 |
| Hartford Bradley Intl Ap, CT | 190 ft | Apr 21 | Oct 16 |
| Burlington, CT | 505 ft | Apr 25 | Oct 18 |
| Bakersville, CT | 686 ft | May 8 | Oct 5 |
Frost dates near Hartford
- Hartford, CT 06161 · last Apr 17, first Oct 26
- West Hartford, CT 06119 · last Apr 17, first Oct 26
- Farmington, CT 06030 · last Apr 17, first Oct 26
- East Hartford, CT 06128 · last Apr 17, first Oct 26
- Wethersfield, CT 06129 · last Apr 17, first Oct 26
- Newington, CT 06131 · last Apr 17, first Oct 26
- Bloomfield, CT 06002 · last Apr 21, first Oct 16
- Windsor, CT 06006 · last Apr 17, first Oct 26
Frequently asked questions
- When is the last frost in Hartford, CT?
- For ZIP code 06103, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Hartford Brainard Fld, CT weather station. There is a 1-in-10 chance of a frost after May 1.
- When is the first frost in Hartford, CT?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 12, so tender plants are at risk from that point on.
- How long is the growing season in 06103?
- 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.