Last spring frost
Apr 17
Frost Dates for Guilford Center, CT
First fall frost
Oct 27
Growing season
193 days
Hardiness zone
7a
In an average year around Guilford Center, CT, the last spring frost (32°F) is about Apr 17 and the first fall frost is about Oct 27, giving roughly a 193-day growing season. To be safe most years, wait until Apr 2 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 12 | Apr 30 | Apr 17 |
| Freeze (32°F) | May 1 | Apr 17 | Apr 2 |
| Hard (28°F) | Apr 18 | Apr 4 | Mar 22 |
| Severe (24°F) | Apr 5 | Mar 25 | Mar 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 12 | May 7 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 17 |
| 32°F | May 1 | Apr 26 | Apr 22 | Apr 20 | Apr 17 | Apr 15 | Apr 11 | Apr 8 | Apr 2 |
| 28°F | Apr 18 | Apr 13 | Apr 9 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 28 | Mar 22 |
| 24°F | Apr 5 | Apr 2 | Mar 31 | Mar 28 | Mar 25 | Mar 20 | Mar 17 | Mar 13 | Mar 7 |
| 20°F | Mar 30 | Mar 25 | Mar 19 | Mar 16 | Mar 13 | Mar 10 | Mar 6 | Mar 1 | Feb 24 |
| 16°F | Mar 22 | Mar 14 | Mar 10 | Mar 6 | Mar 2 | Feb 27 | Feb 23 | Feb 17 | Feb 9 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 4 | Oct 15 | Nov 1 |
| Freeze (32°F) | Oct 11 | Oct 27 | Nov 8 |
| Hard (28°F) | Oct 22 | Nov 6 | Nov 21 |
| Severe (24°F) | Nov 1 | Nov 19 | Dec 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 4 | Oct 6 | Oct 9 | Oct 13 | Oct 15 | Oct 18 | Oct 22 | Oct 26 | Nov 1 |
| 32°F | Oct 11 | Oct 16 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 8 |
| 28°F | Oct 22 | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 21 |
| 24°F | Nov 1 | Nov 7 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 6 |
| 20°F | Nov 15 | Nov 22 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 12 | Dec 17 | Dec 24 |
| 16°F | Dec 1 | Dec 7 | Dec 11 | Dec 16 | Dec 20 | Dec 23 | Dec 28 | Jan 2 | Jan 10 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: New Haven Tweed Ap, Ct, about 10.9 miles away@if(!empty($station['elevation_ft'])), at 3 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Guilford Center, CT?
On average, the last spring frost (32°F) around Guilford Center, CT is about Apr 17. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 2.
When is the first frost in the fall?
The first fall frost around Guilford Center, CT typically arrives about Oct 27. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 17 on average, or Apr 2 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 193 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 06437 Planting calendar → Connecticut frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026