Frost dates / By state
Frost dates in Connecticut
NOAA 1991–2020 normals for a 32 °F freeze. Your own yard can run a little either side.
Short answer
Across 8 NOAA weather stations in Connecticut, the average last spring frost runs from April 5 at Bridgeport Sikorsky Mem Airport to May 1 at Danbury Muni Airport. The first fall frost comes as early as October 13 at Willimantic Windham Airport and as late as November 6 at Bridgeport Sikorsky Mem Airport. Planting zones near these stations run from 6b to 7a.
Connecticut cities
- Frost dates in Bridgeport: last frost April 5, first frost November 6
Find yours by ZIP code
The table below is by weather station. For the station nearest you, and your planting zone, type your ZIP code.
Connecticut frost dates by weather station
| Station | Last spring frost | First fall frost | Frost-free | Zone nearby |
|---|---|---|---|---|
| Bridgeport Sikorsky Mem Airport 5 ft | April 5 1 in 10 after April 17 | November 6 1 in 10 by October 25 | 215 days | 7a |
| Danbury Muni Airport 457 ft | May 1 1 in 10 after May 16 | October 14 1 in 10 by October 1 | 166 days | 6b |
| Groton New London Airport 10 ft | April 16 1 in 10 after April 30 | October 28 1 in 10 by October 13 | 195 days | 7a |
| Hartford Bradley Intl Airport 190 ft | April 21 1 in 10 after May 6 | October 16 1 in 10 by October 3 | 178 days | 6b |
| Hartford Brainard Fld 19 ft | April 17 1 in 10 after May 1 | October 26 1 in 10 by October 12 | 192 days | 6b |
| Meriden Markham Muni Airport 103 ft | April 26 1 in 10 after May 9 | October 16 1 in 10 by October 4 | 173 days | 6b |
| New Haven Tweed Airport 3 ft | April 17 1 in 10 after May 1 | October 27 1 in 10 by October 11 | 193 days | 7a |
| Willimantic Windham Airport 247 ft | April 28 1 in 10 after May 11 | October 13 1 in 10 by October 2 | 168 days | 6b |
The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. Stations are NOAA's main weather stations, mostly airports. “Zone nearby” is the USDA 2023 zone of the nearest ZIP code within 10 miles. NOAA counts the frost season from August to July, so in the warmest places the “first fall” freeze lands after New Year.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
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Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)