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 98660
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 98660 in zone 8b (the coldest night of a typical year: 15 to 20°F).
The nearest station, Hazel Dell, WA, is 3 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 8b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Hazel Dell, WAVancouver (4 mi NNE) | 3 mi | 210 ft | April 26 | May 10 | October 18 | 8b |
| Vancouver, WAVancouver Pearson Airport | 4 mi | 30 ft | March 29 | April 18 | November 9 | 8b |
| Portland, ORPortland International Airport | 8 mi | 19 ft | March 13 | April 1 | November 19 | 9a |
| Portland Kgw-Tv, OR | 10 mi | 159 ft | February 25 | March 21 | December 1 | 9a |
| Scappoose, ORScappoose Ind Airport | 10 mi | 55 ft | April 10 | May 1 | November 2 | 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 Hazel Dell
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 30 | May 19 | May 10 | April 28 | October 1 | September 14 |
| 32°F | May 10 | May 1 | April 26 | April 7 | October 18 | October 1 |
| 28°F (hard freeze) | April 20 | April 6 | March 30 | March 8 | November 4 | October 16 |
| 24°F | March 26 | March 10 | February 28 | February 1 | November 26 | October 28 |
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.