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 99801
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 99801 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Annex Creek, AK, is 5 miles from the ZIP's center: its last spring frost comes after May 3 in half of years and after May 18 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Annex Creek, AK | 5 mi | 92 ft | May 3 | May 18 | October 14 | – |
| Juneau Downtown, AK | 10 mi | 50 ft | April 20 | May 5 | October 22 | – |
| Eaglecrest Base, AK | 14 mi | 1,134 ft | May 21 | June 2 | October 1 | – |
| Juneau, AKJuneau Airport | 14 mi | 16 ft | May 4 | May 18 | October 3 | 6b |
| Juneau Forecast Office, AK | 14 mi | 106 ft | May 9 | May 24 | October 4 | 6a |
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 Annex Creek
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) | June 1 | May 25 | May 19 | May 4 | September 29 | September 17 |
| 32°F | May 18 | May 9 | May 3 | April 18 | October 14 | October 1 |
| 28°F (hard freeze) | April 30 | April 18 | April 11 | March 26 | October 31 | October 14 |
| 24°F | April 9 | April 1 | March 27 | March 10 | November 13 | October 30 |
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.