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 98056
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 98056 in zone 9a (the coldest night of a typical year: 20 to 25°F).
The nearest station, Renton, WA, is 2 miles from the ZIP's center: its last spring frost comes after March 13 in half of years and after March 31 in one year in ten. By the USDA's method its plant hardiness zone is 9a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Renton, WARenton Municipal Airport | 2 mi | 29 ft | March 13 | March 31 | November 16 | 9a |
| Seattle Boeing Field, WA | 5 mi | 20 ft | March 13 | April 1 | November 17 | 9a |
| Kent, WA | 7 mi | 30 ft | March 20 | April 8 | November 10 | 8b |
| Seattle, WASeattle Tacoma International Airport | 8 mi | 370 ft | March 2 | March 23 | November 23 | 9a |
| Seattle Sand Point Weather Office, WA | 12 mi | 60 ft | March 8 | March 29 | November 23 | 9a |
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 Renton
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) | April 25 | April 14 | April 6 | March 21 | October 31 | October 17 |
| 32°F | March 31 | March 22 | March 13 | February 19 | November 16 | October 29 |
| 28°F (hard freeze) | March 6 | February 24 | February 13 | January 1 | December 6 | November 11 |
| 24°F | February 22 | February 4 | January 8 | December 3 | December 19 | November 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.