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 99725
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 99725 in zone 3b (the coldest night of a typical year: -35 to -30°F).
The nearest station, Ester, AK, is 1 miles from the ZIP's center: its last spring frost comes after May 24 in half of years and after June 4 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Ester, AK | 1 mi | 655 ft | May 24 | June 4 | September 1 | – |
| University Experiment Station, AK | 5 mi | 475 ft | May 16 | May 30 | September 8 | 2b |
| College, AKCollege Obsy | 5 mi | 597 ft | May 18 | June 1 | September 6 | 2b |
| Fairbanks Airport #2, AK | 5 mi | 427 ft | May 16 | May 30 | September 8 | – |
| Fairbanks, AKFairbanks International Airport | 6 mi | 432 ft | May 13 | May 26 | September 13 | 2a |
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 Ester
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 22 | June 9 | June 4 | May 24 | August 21 | August 8 |
| 32°F | June 4 | May 29 | May 24 | May 12 | September 1 | August 19 |
| 28°F (hard freeze) | May 27 | May 18 | May 13 | May 3 | September 11 | August 30 |
| 24°F | May 17 | May 9 | May 5 | April 23 | September 21 | September 8 |
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.