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 98029
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 98029 in zone 8b (the coldest night of a typical year: 15 to 20°F).
The nearest station, Snoqualmie, WA, is 8 miles from the ZIP's center: its last spring frost comes after March 30 in half of years and after April 21 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Snoqualmie, WASnoqualmie Falls | 8 mi | 440 ft | March 30 | April 21 | November 7 | – |
| Renton, WARenton Municipal Airport | 10 mi | 29 ft | March 13 | March 31 | November 16 | 9a |
| Landsburg, WA | 13 mi | 535 ft | April 20 | May 10 | October 25 | 8b |
| Seattle Boeing Field, WA | 14 mi | 20 ft | March 13 | April 1 | November 17 | 9a |
| Seattle Sand Point Weather Office, WA | 14 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 Snoqualmie
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 13 | May 2 | April 26 | April 8 | October 22 | October 4 |
| 32°F | April 21 | April 8 | March 30 | March 4 | November 7 | October 22 |
| 28°F (hard freeze) | March 25 | March 9 | February 27 | January 16 | November 29 | November 6 |
| 24°F | February 28 | February 17 | January 31 | December 6 | December 18 | November 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.