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Frost Dates in Connecticut
First and last frost dates across Connecticut, computed from 13 NOAA weather stations (1991–2020 climate normals). Your exact date depends on your city and microclimate — use the ZIP lookup on the main tool for a station-specific answer.
Last spring frost
Apr 18
statewide median · range Apr 5–May 8
First fall frost
Oct 23
statewide median · range Oct 5–Nov 6
Growing season
188 days
median · range 151–216
Stations used
13
NOAA 1991–2020 normals
Frost dates by city
Median dates from the nearest NOAA station to each city. The "cautious" date is the 10% spring value — planting after it means only a ~10% chance of a later frost.
| City | Nearest station | Last spring frost | First fall frost | Growing season | Safe transplant |
|---|---|---|---|---|---|
| Hartford | Hartford Brainard Fld · 2 mi | Apr 17 (cautious: May 1) | Oct 26 | 191 days | May 1 |
| New Haven | New Haven Tweed Ap · 4 mi | Apr 17 (cautious: May 1) | Oct 27 | 193 days | May 1 |
| Stamford | Stamford 5 N · 5 mi | Apr 17 (cautious: May 2) | Oct 23 | 188 days | May 1 |
How frost varies across Connecticut
Spring frost timing spans about 33 days across the state. Igor I Sikorsky Mem in Connecticut typically sees its last spring frost around April 5, while Bakersville in Connecticut doesn't clear frost until about May 8. Within any city, low spots and valleys run colder than the station average; areas near buildings and pavement run warmer.
When to plant in Connecticut
As a rule of thumb, cool-season crops (lettuce, peas, spinach) can go in 2–4 weeks before your last spring frost; warm-season transplants (tomatoes, peppers) should wait about 2 weeks after it — around May 2 for the statewide median. Check your city's row above rather than the statewide median: a 33-day statewide spread makes the city-level date the one that matters.
These are climate normals (what's typical), not forecasts. For the current year, watch the 10-day forecast around your planting date.
How this is computed
Statewide medians are the median of the 13 NOAA stations' median frost dates — half the stations run earlier, half later. City rows use the nearest station with 30-year freeze records. Dates are 32°F freeze probabilities from NOAA NCEI 1991–2020 U.S. Climate Normals; nothing is estimated or interpolated.
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Frequently asked questions
When is the last frost date in Connecticut?
The statewide median last spring frost is April 18, but it ranges from April 5 to May 8 depending on where in the state you are. Use your city's row in the table above, or the ZIP lookup on the main tool, for a station-specific date.
When can I plant tomatoes outside in Connecticut?
Warm-season transplants like tomatoes should wait about two weeks after your last spring frost — around May 2 for the statewide median. Your city may differ by weeks; check the "safe transplant" column in the city table.
How long is the growing season in Connecticut?
The median growing season across 13 NOAA stations is 188 days, ranging from 151 to 216 days by location.
Why do frost dates vary so much within Connecticut?
Frost timing follows latitude, elevation, and local terrain. Across Connecticut, last spring frost dates span about 33 days — from around April 5 near Igor I Sikorsky Mem to May 8 near Bakersville. Microclimates (low spots, valleys, urban heat) shift dates further at the garden level.
Where does this data come from?
All frost dates are computed from the NOAA National Centers for Environmental Information 1991–2020 U.S. Climate Normals freeze data (public domain), using each station's 32°F freeze probability statistics. No dates are estimated or interpolated.