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 37615
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 37615 in zone 7b (the coldest night of a typical year: 5 to 10°F).
The nearest station, Bristol, TN, is 6 miles from the ZIP's center: its last spring frost comes after April 16 in half of years and after May 5 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 |
|---|---|---|---|---|---|---|
| Bristol, TNBristol Airport | 6 mi | 1,500 ft | April 16 | May 5 | October 24 | 7a |
| Kingsport, TN | 9 mi | 1,284 ft | April 9 | April 25 | October 29 | 7b |
| Elizabethton, TN | 12 mi | 1,487 ft | April 19 | May 7 | October 24 | 7a |
| Erwin, TN1 mi W | 18 mi | 1,720 ft | April 21 | May 11 | October 23 | 7a |
| Roan Mountain, TN3 mi SW | 26 mi | 2,923 ft | April 30 | May 16 | October 12 | – |
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 Bristol
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 17 | May 6 | April 29 | April 14 | October 15 | October 4 |
| 32°F | May 5 | April 22 | April 16 | March 30 | October 24 | October 11 |
| 28°F (hard freeze) | April 18 | April 8 | April 1 | March 16 | November 1 | October 19 |
| 24°F | April 5 | March 27 | March 21 | February 28 | November 12 | October 30 |
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.