Frost dates for Hartford, Connecticut
In Hartford, half of springs have had their last frost by April 17 (and 1 spring in 10 still has one after May 1), and half of falls have had their first frost by October 26, leaving about 191 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Hartford, Connecticut
Last spring frost
April 17
Half of springs have their last frost by this date. For a safer bet, wait until May 1: only 1 spring in 10 has a frost after that.
First fall frost
October 26
Half of falls have their first frost by this date. In 1 fall in 10 it comes by October 12.
Growing season
191 days
Frost-free days in a typical year. 9 years in 10 get at least 169.
Hardiness zone
6b
2023 USDA map: the coldest night of winter averages −5°F to 0°F. It was 6b on the 2012 map too. All 15 ZIP codes within about 6 miles of the city's center are in zone 6b.
Print a year planner for Hartford
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | April 1 | April 17 | May 1 |
| First frost in fall | October 12 | October 26 | November 7 |
The frost-free season between them runs 191 days in a typical year. In 1 year in 10 it is 212 days or longer, and in 1 year in 10 it is 169 days or shorter.
- Hard freeze (28°F): typically last on April 3 and first on November 5. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on April 30 and first on October 14. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Hartford comes between April 1 and May 1, a window of 30 days. That is about average for NOAA's stations (the typical window is 31 days).
Among Connecticut's 23 NOAA stations with a frost every year, 70 percent have their typical last frost later than Hartford does.
Planting calendar for Hartford
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 30 to February 27 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| February | ||
| February 13 to March 13 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| February 27 to March 20 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| March | ||
| March 6 to 20 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| March 13 to 27 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| March 20 to April 3 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 20 to April 3 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April | ||
| April 3 to 17 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| April 3 to 17 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| April 17 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| May | ||
| May 1 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| May 1 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| May 31 to June 14 | Cabbage for fall Start seeds | set the plants out by July 19 |
| June | ||
| June 20 to July 4 | Broccoli for fall Start seeds | set the plants out by August 8 |
| July | ||
| July 30 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August | ||
| August 3 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 4 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 8 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| August 9 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 13 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| August 23 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 2 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| September 12 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 12 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| November | ||
| November 12 to 19 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
Want more insurance? Shift every spring date 14 days later. That plans around May 1, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Hartford Brainard Field (station USW00014752), 3 miles from the center of Hartford. It sits at about the same elevation, 20 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
The same station also gives the frost dates for New Britain.
Our ZIP code lookup matches these 23 ZIP codes to the same station, so they get the same dates: 06032, 06033, 06040, 06042, 06051, 06067, 06073, 06074, 06103, 06105, 06106, 06107, 06108, 06109, 06110, 06111, 06112, 06114, 06118, 06119, 06120, 06416, 06480. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Waterbury, Connecticut: last frost around April 26, first frost around October 16 (25 miles away)
- Springfield, Massachusetts: last frost around May 3, first frost around October 8 (25 miles away)
- New Haven, Connecticut: last frost around April 17, first frost around October 27 (35 miles away)
See frost dates across Connecticut, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.