Frost dates by ZIP code: The nearest NOAA stations to your ZIP, 1991-2020 normals
Enter a five-digit ZIP code. PlainClimate finds its center (Census Bureau 2024) and the five nearest NOAA stations with frost dates, and shows each station's last spring and first autumn 32°F dates with its distance and elevation.
Frost dates near ZIP 06511
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 06511 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, New Haven, CT, is 4 miles from the ZIP's center: its last spring frost comes after April 17 in half of years and after May 1 in one year in ten. By the USDA's method its plant hardiness zone is 7a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| New Haven, CTNew Haven Tweed Airport | 4 mi | 3 ft | April 17 | May 1 | October 27 | 7a |
| Mount Carmel, CT | 6 mi | 180 ft | April 18 | May 3 | October 26 | 6b |
| Ansonia, CT1 mi NE | 9 mi | 136 ft | April 25 | May 10 | October 17 | – |
| Meriden, CTMeriden Markham Municipal Airport | 14 mi | 103 ft | April 26 | May 9 | October 16 | 6b |
| Bridgeport, CTIgor I Sikorsky Memorial Airport | 15 mi | 5 ft | April 5 | April 17 | November 6 | 7a |
Frost comes later in spring at higher and colder stations and earlier in low, open ground: prefer a station at a similar elevation to yours. Hardiness zone in the table: the USDA's rule (the average of each year's coldest night, 1991-2020) applied to the station's own record.
Every frost threshold at New Haven
NOAA publishes the dates for several temperatures and odds. A 30% spring date means a 3-in-10 chance of a later frost (the convention almanacs use); 50% is the median; 10% the cautious date.
| Threshold | Spring, 10% | Spring, 30% | Spring, 50% | Spring, 90% | Autumn, 50% | Autumn, 10% |
|---|---|---|---|---|---|---|
| 36°F (light frost) | May 12 | May 4 | April 30 | April 17 | October 15 | October 4 |
| 32°F | May 1 | April 22 | April 17 | April 2 | October 27 | October 11 |
| 28°F (hard freeze) | April 18 | April 9 | April 4 | March 22 | November 6 | October 22 |
| 24°F | April 5 | March 31 | March 25 | March 7 | November 19 | November 1 |
Source: NOAA NCEI 1991-2020 annual normals; ZIP centers: Census Bureau 2024 Gazetteer; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. Autumn 10%: one year in ten has its first frost before this date.