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 83651
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 83651 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Nampa, ID, is 3 miles from the ZIP's center: its last spring frost comes after April 29 in half of years and after May 18 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 |
|---|---|---|---|---|---|---|
| Nampa, IDNampa Sugar Factory | 3 mi | 2,470 ft | April 29 | May 18 | October 13 | 7a |
| Deer Flat Dam, ID | 6 mi | 2,510 ft | April 23 | May 9 | October 18 | – |
| Homedale, ID1 mi SE | 15 mi | 2,230 ft | April 24 | May 5 | October 9 | – |
| Boise, IDBoise Air Terminal | 19 mi | 2,814 ft | April 24 | May 9 | October 21 | 7b |
| Emmett, ID2 mi E | 20 mi | 2,390 ft | April 30 | May 17 | October 17 | 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 Nampa
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) | June 6 | May 24 | May 16 | May 1 | September 30 | September 15 |
| 32°F | May 18 | May 5 | April 29 | April 15 | October 13 | September 29 |
| 28°F (hard freeze) | May 1 | April 20 | April 11 | March 25 | October 25 | October 9 |
| 24°F | April 12 | April 1 | March 22 | March 2 | November 6 | October 22 |
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.