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 99206
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 99206 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Spokane Felts Field, WA, is 5 miles from the ZIP's center: its last spring frost comes after April 26 in half of years and after May 10 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 |
|---|---|---|---|---|---|---|
| Spokane Felts Field, WA | 5 mi | 1,953 ft | April 26 | May 10 | October 15 | 7a |
| Spokane, WASpokane International Airport | 13 mi | 2,353 ft | April 26 | May 10 | October 12 | 6b |
| Spokane Weather Office, WA | 18 mi | 2,392 ft | May 10 | May 30 | September 26 | – |
| Spokane (17 mi SSW), WA | 19 mi | 2,267 ft | May 30 | July 13 | September 4 | – |
| Coeur d'Alene, IDCoeur D'alene | 22 mi | 2,133 ft | April 22 | May 6 | October 18 | 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 Spokane Felts Field
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 25 | May 15 | May 9 | April 27 | October 1 | September 19 |
| 32°F | May 10 | May 1 | April 26 | April 10 | October 15 | September 30 |
| 28°F (hard freeze) | April 26 | April 13 | April 4 | March 16 | October 27 | October 11 |
| 24°F | March 30 | March 19 | March 12 | February 25 | November 8 | October 21 |
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.