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 98074
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 98074 in zone 8b (the coldest night of a typical year: 15 to 20°F).
The nearest station, Seattle Sand Point Weather Office, WA, is 11 miles from the ZIP's center: its last spring frost comes after March 8 in half of years and after March 29 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 |
|---|---|---|---|---|---|---|
| Seattle Sand Point Weather Office, WA | 11 mi | 60 ft | March 8 | March 29 | November 23 | 9a |
| Snoqualmie, WASnoqualmie Falls | 11 mi | 440 ft | March 30 | April 21 | November 7 | – |
| Renton, WARenton Municipal Airport | 12 mi | 29 ft | March 13 | March 31 | November 16 | 9a |
| Seattle Boeing Field, WA | 14 mi | 20 ft | March 13 | April 1 | November 17 | 9a |
| Monroe, WA | 16 mi | 120 ft | April 17 | May 7 | October 23 | 8b |
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 Seattle Sand Point Weather Office
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 26 | April 12 | April 4 | March 17 | November 5 | October 24 |
| 32°F | March 29 | March 16 | March 8 | February 13 | November 23 | November 4 |
| 28°F (hard freeze) | March 1 | February 21 | February 11 | December 27 | December 11 | November 17 |
| 24°F | February 20 | February 3 | January 9 | December 3 | December 24 | November 27 |
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.