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 37924
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 37924 in zone 7b (the coldest night of a typical year: 5 to 10°F).
The nearest station, Knoxville Experiment Station, TN, is 12 miles from the ZIP's center: its last spring frost comes after April 11 in half of years and after April 29 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 |
|---|---|---|---|---|---|---|
| Knoxville Experiment Station, TN | 12 mi | 830 ft | April 11 | April 29 | October 28 | 7b |
| Sevierville, TN | 14 mi | 899 ft | April 6 | April 21 | October 29 | 7b |
| Knoxville, TNKnoxville Airport | 17 mi | 962 ft | April 1 | April 17 | November 2 | 7b |
| Norris, TN | 19 mi | 1,110 ft | April 22 | May 9 | October 25 | 7b |
| Jefferson City, TN | 20 mi | 1,108 ft | April 24 | May 13 | October 17 | – |
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 Knoxville Experiment Station
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 | May 1 | April 24 | April 9 | October 19 | October 7 |
| 32°F | April 29 | April 19 | April 11 | March 26 | October 28 | October 13 |
| 28°F (hard freeze) | April 16 | April 5 | March 31 | March 13 | November 6 | October 24 |
| 24°F | April 5 | March 26 | March 18 | February 26 | 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.