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 83704
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 83704 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Boise, ID, is 5 miles from the ZIP's center: its last spring frost comes after April 24 in half of years and after May 9 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 |
|---|---|---|---|---|---|---|
| Boise, IDBoise Air Terminal | 5 mi | 2,814 ft | April 24 | May 9 | October 21 | 7b |
| Boise (7 mi N), ID | 9 mi | 3,885 ft | May 17 | June 10 | October 12 | 7a |
| Boise Lucky Peak Dam, ID | 14 mi | 2,840 ft | April 30 | May 18 | October 22 | – |
| Nampa, IDNampa Sugar Factory | 14 mi | 2,470 ft | April 29 | May 18 | October 13 | 7a |
| Emmett, ID2 mi E | 18 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 Boise
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 29 | May 14 | May 8 | April 23 | October 8 | September 25 |
| 32°F | May 9 | April 30 | April 24 | April 4 | October 21 | October 5 |
| 28°F (hard freeze) | April 25 | April 12 | April 2 | March 10 | October 31 | October 17 |
| 24°F | April 4 | March 19 | March 9 | February 16 | November 13 | October 24 |
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.