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 06256
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 06256 in zone 6b (the coldest night of a typical year: -5 to 0°F).
The nearest station, Willimantic, CT, is 2 miles from the ZIP's center: its last spring frost comes after April 28 in half of years and after May 11 in one year in ten. By the USDA's method its plant hardiness zone is 6b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Willimantic, CTWillimantic Windham Airport | 2 mi | 247 ft | April 28 | May 11 | October 13 | 6b |
| Storrs, CT | 6 mi | 665 ft | April 19 | May 3 | October 22 | 6b |
| Hampton, CT | 6 mi | 490 ft | April 30 | May 11 | October 15 | – |
| Norwich, CTNorwich Public Utility Plant | 15 mi | 20 ft | April 14 | April 30 | October 24 | 7a |
| Staffordville, CT | 19 mi | 736 ft | May 7 | May 21 | October 12 | 6a |
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 Willimantic
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 22 | May 14 | May 9 | April 27 | October 3 | September 23 |
| 32°F | May 11 | May 3 | April 28 | April 17 | October 13 | October 2 |
| 28°F (hard freeze) | April 29 | April 20 | April 14 | April 2 | October 25 | October 10 |
| 24°F | April 15 | April 5 | April 2 | March 17 | November 5 | October 21 |
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.