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Connecticut Frost Dates: Last and First Frost by Town

23 NOAA weather stations · 1991–2020 U.S. Climate Normals · Data updated 2026-10-29

Quick answer

Across Connecticut's 23 NOAA stations with regular frost, the median last spring frost is April 25 and the median first fall frost is October 17. Last frost dates range from April 5 at Bridgeport Sikorsky Memorial Airport to May 11 at Falls Village, so enter your ZIP code below for the station nearest you.

How frost dates vary across Connecticut

  • North vs south: stations in the northern third of the state (north of 41.8°N) reach their median last frost about 16 days later than the southern third (south of 41.4°N).
  • Safety margin: the median 10%-risk date (May 9) is about 14 days after the median last frost. Waiting until then cuts the chance of a killing frost on tender transplants from 1 in 2 to 1 in 10.

Frost dates at Connecticut's major weather stations

These National Weather Service stations, mostly at airports, have the longest and most complete records in the state.
Bridgeport Sikorsky Memorial Airport5Apr 5Apr 17Nov 6216
Danbury Municipal Airport457May 1May 16Oct 14166
Groton New London Airport10Apr 16Apr 30Oct 28194
Hartford Bradley Intl Airport190Apr 21May 6Oct 16177
Hartford Brainard Field19Apr 17May 1Oct 26191
Meriden Markham Municipal Airport103Apr 26May 9Oct 16175
New Haven Tweed Airport3Apr 17May 1Oct 27193
Willimantic Windham Airport247Apr 28May 11Oct 13167

All 23 stations in Connecticut

Last frost and first frost are medians: a 50% chance of a 32°F night after (spring) or before (fall) that date. 10% risk is the spring date with only a 1-in-10 chance of a later frost. Click a column to sort.
Ansonia 1 NE136Apr 25May 10Oct 17175
Bakersville686May 8May 22Oct 5151
Barkhamsted710Apr 30May 15Oct 17168
Bridgeport Sikorsky Memorial Airport5Apr 5Apr 17Nov 6216
Burlington505Apr 25May 10Oct 18172
Danbury405Apr 20May 6Oct 20181
Danbury Municipal Airport457May 1May 16Oct 14166
Falls Village550May 11May 27Oct 4146
Groton40Apr 8Apr 22Nov 2207
Groton New London Airport10Apr 16Apr 30Oct 28194
Hampton490Apr 30May 11Oct 15167
Hartford Bradley Intl Airport190Apr 21May 6Oct 16177
Hartford Brainard Field19Apr 17May 1Oct 26191
Meriden Markham Municipal Airport103Apr 26May 9Oct 16175
Mount Carmel180Apr 18May 3Oct 26191
New Haven Tweed Airport3Apr 17May 1Oct 27193
Norfolk 2 SW1,340May 3May 17Oct 11161
Norwich Public Utility Plt20Apr 14Apr 30Oct 24192
Staffordville736May 7May 21Oct 12159
Stamford 5 N190Apr 17May 2Oct 23188
Storrs665Apr 19May 3Oct 22186
W Thompson Lake360May 1May 17Oct 9161
Willimantic Windham Airport247Apr 28May 11Oct 13167

Frequently asked questions

When is the last frost in Connecticut?

The median last spring frost (32°F) across Connecticut's NOAA weather stations is April 25, based on 1991–2020 climate normals. It ranges from April 5 at Bridgeport Sikorsky Memorial Airport to May 11 at Falls Village. For a safer planting date, use the 10%-risk date; the state median for that is May 9.

When is the first frost in Connecticut?

The median first fall frost across Connecticut's stations is October 17. The earliest median first frost is October 4 at Falls Village, and the latest is November 6 at Bridgeport Sikorsky Memorial Airport.

How long is the growing season in Connecticut?

The median frost-free season is 175 days across Connecticut's stations, from 146 days at Falls Village to 216 days at Bridgeport Sikorsky Memorial Airport.

When should I plant tomatoes in Connecticut?

Plant tomatoes outdoors after your local last frost, ideally after the 10%-risk date when nights stay above 50°F. At a typical Connecticut station that means starting seeds indoors 6–8 weeks before April 25 and transplanting from about May 9. Check your ZIP code, because dates vary by weeks across the state.

How to use these dates

Frost dates are 30-year averages from NOAA, not forecasts. Use them to plan seed starting and planting, then watch the 10-day forecast as the date approaches. Cold air settles in valleys and low spots, so a garden at the bottom of a slope can frost a week or more later in spring than the nearest station shows.

Ready to plan? The planting calendar by ZIP code turns these dates into start-indoors, transplant and sowing dates for 30 crops.

Sources and method

Dates are the 32°F freeze probabilities published in the NOAA NCEI 1991–2020 U.S. Climate Normals for each station. Station names are NOAA's, lightly expanded for readability. See the methodology or download the full table.

Frost dates in other states