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 37663
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 37663 in zone 7b (the coldest night of a typical year: 5 to 10°F).
The nearest station, Kingsport, TN, is 4 miles from the ZIP's center: its last spring frost comes after April 9 in half of years and after April 25 in one year in ten. By the USDA's method its plant hardiness zone is 7b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Kingsport, TN | 4 mi | 1,284 ft | April 9 | April 25 | October 29 | 7b |
| Bristol, TNBristol Airport | 5 mi | 1,500 ft | April 16 | May 5 | October 24 | 7a |
| Elizabethton, TN | 15 mi | 1,487 ft | April 19 | May 7 | October 24 | 7a |
| Erwin, TN1 mi W | 22 mi | 1,720 ft | April 21 | May 11 | October 23 | 7a |
| Rogersville, TN1 mi NE | 28 mi | 1,355 ft | April 14 | May 3 | October 24 | 7b |
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 Kingsport
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 10 | April 30 | April 23 | April 6 | October 20 | October 6 |
| 32°F | April 25 | April 16 | April 9 | March 25 | October 29 | October 15 |
| 28°F (hard freeze) | April 12 | April 2 | March 28 | March 10 | November 6 | October 25 |
| 24°F | March 31 | March 23 | March 15 | February 25 | November 18 | November 4 |
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.