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 50012
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 50012 in zone 5b (the coldest night of a typical year: -15 to -10°F).
The nearest station, Ames, IA, is 3 miles from the ZIP's center: its last spring frost comes after April 26 in half of years and after May 9 in one year in ten. By the USDA's method its plant hardiness zone is 5a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Ames, IAAmes Municipal Airport | 3 mi | 930 ft | April 26 | May 9 | October 8 | 5a |
| Ames (8 mi WSW), IA | 6 mi | 1,099 ft | April 23 | May 5 | October 14 | – |
| Ames (5 mi SE), IA | 7 mi | 870 ft | April 26 | May 8 | October 12 | 5a |
| Boone, IA | 12 mi | 1,035 ft | April 28 | May 11 | October 12 | 5a |
| Colo, IA | 17 mi | 1,000 ft | April 24 | May 7 | October 12 | 5b |
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 Ames
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 17 | May 10 | May 5 | April 21 | September 28 | September 15 |
| 32°F | May 9 | May 2 | April 26 | April 11 | October 8 | September 23 |
| 28°F (hard freeze) | May 1 | April 21 | April 14 | April 1 | October 19 | October 4 |
| 24°F | April 21 | April 10 | April 4 | March 17 | October 29 | October 16 |
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.